About your question about salvaging giant its quite good move to do as you will have one weak card less. On more serious note main problem of article is that there isn't much knowledge - it mostly states what would average player thing when he first sees boards with giant. It would need more strategic advices.
I would expect giant to be card that loses most ranks this year in quist ranking as its a bottom tier card that was ranked average previous year. Most important part about giant strategy is when to skip it which this article doesn't address. Best way to decide that is to generate lot of boards and think if giant is part of optimal strategy. To keep same random seed lets use following boards.
http://gokosalvager.com/logsearch?p1name=&p1score=any&p2name=&startdate=08%2F05%2F2012&enddate=12%2F28%2F2016&supply=giant&nonsupply=&rating=professional&pcount=2&colony=any&bot=false&shelters=any&guest=false&minturns=&maxturns=&quit=false&resign=any&submitted=true&offset=0Provinces / Estates - Cellar, Copper, Curse, Duchy, Embargo, Estate, Feast, Giant, Gold, Hunting Party, Mining Village, Province, Sage, Scavenger, Silk Road, Silver, Storyteller, Ball
Scavenger-hunting party mirror, nobody bought giant.
Provinces / Estates - Altar, Band of Misfits, Copper, Curse, Duchy, Estate, Fairgrounds, Giant, Gold, Guide, Herbalist, Militia, Mystic, Nomad Camp, Province, Silver, Urchin, Mission
Here I disagree with players strategy. Mercenary is key here with mission/guide support. Giant isn't that good due terminal collision and millitia would be better if opponent doesn't pick any guides. Best use of giant is for fairgrounds points. So its 1/2 for giant.
Provinces / Estates - Chancellor, Copper, Curse, Distant Lands, Duchy, Estate, Forager, Giant, Gold, Grand Market, Highway, Hireling, Masterpiece, Mine, Province, Royal Seal, Silver, Alms
Obvious highway/grand market engine with forager/hireling/alms+highway support. One player opened giant instead of highway and lost as he deserved.
Provinces / Estates - Band of Misfits, Copper, Cultist, Curse, Duchy, Estate, Giant, Gold, Noble Brigand, Philosopher's Stone, Potion, Province, Royal Carriage, Ruins, Scrying Pool, Silver, Transmogrify, Treasure Trove, Courtyard
Obvious cultist board transitioned into ttrove/pstone. Players didn't play this that well but one got giant instead cultist and lost again.
Provinces / Estates - Copper, Curse, Duchy, Embassy, Estate, Fairgrounds, Feast, Giant, Gold, Hermit, Library, Messenger, Province, Royal Carriage, Silver, Treasure Map, Wishing Well, Trade
Here both players did treasure map hermit. Alternative is embassy bm with trade support. Either way giant is ignorable.
Provinces / Shelters - Armory, Band of Misfits, Copper, Curse, Duchy, Estate, Fortress, Giant, Gold, Hireling, Menagerie, Mine, Oasis, Province, Ratcatcher, Silver, Training, Treasure Map, Pilgrimage
Again here both players ignored giant. While they misplayed it doesn't change giant usefulness. Here one wants to use bom/arory to get menageries and training on them with some ratcatcher trashing. Midgame tmap is possible if you got 2-3 bom to guarantee collision.
Colonies, Estates - Butcher, City, Colony, Copper, Crossroads, Curse, Duchy, Estate, Giant, Gold, Horse Traders, Plan, Platinum, Poor House, Prince, Province, Silver, Swamp Hag, Talisman, Trader, Quest
This was misplayed, both players got giants and one got 6 without village support. Here i am not sure if giant or swamp hag are better for spiking platinum so 1/2 for giant.
Provinces / Estates - Copper, Curse, Duchy, Estate, Farming Village, Fortress, Giant, Gold, Great Hall, Library, Outpost, Pawn, Province, Remake, Silver, Tribute, Herbalist
Here both players got giant early which is mistake. But it is rare board where you want giant as giant+pawn are only sources of virtual coin for draw-to-x engine. Attack part here is irrelevant as you want 2 remakes for trashing and remaking fortress. If one gets giant after he could draw deck with 2-3 libraries it would work. So point for giant
Provinces / Estates - Copper, Curse, Duchy, Estate, Forge, Giant, Gold, Great Hall, Hunting Grounds, Province, Secret Chamber, Silver, Squire, Talisman, Torturer, Warehouse, Crossroads
Torturer engine - giant has no place there as torturer helps/hurts more, one player gets giant and loses despite poor play of second one (opening great hall).
Provinces / Shelters - Copper, Curse, Doctor, Duchy, Dungeon, Estate, Festival, Giant, Gold, Hireling, Hunting Grounds, Island, Menagerie, Province, Rats, Rebuild, Silver, Scouting Party
Rebuild game, nobody gets giant. I am skeptical that it would outpace rebuild here as with dungeon/scouting party it looks too fast.
Provinces / Estates - Coin of the Realm, Copper, Curse, Distant Lands, Duchy, Estate, Feast, Giant, Gold, Market, Militia, Peasant, Province, Ranger, Remodel, Silver, Trade, Transmogrify, Borrow
Here both players missed ranger-cotr engine with peasant to supercharge. Opening remodel to get convert copper into cotr looks good. Avoid giant as you don't have actions to support it (including distant lands in midgame) and it will mess ranger journey tokens as you want 5 cards from ranger instead of 5 coins from giant here.
Provinces / Estates - Caravan Guard, Copper, Council Room, Crossroads, Curse, Duchy, Estate, Fairgrounds, Giant, Gold, Grand Market, Mandarin, Province, Ranger, Silk Road, Silver, Training, Wandering Minstrel, Travelling Fair
Here both players got giant, and here its bit reasonable for faigrounds points. It isn't good source of coins here as training on minstrel is better and you want draw here and giant conflict bit with ranger again. So here its 1/2 for giant if you could buy and play 2 giants after you could draw your deck but I am not convinced yet its better than golds.
Provinces / Estates - Border Village, Bridge, Copper, Curse, Duchy, Envoy, Estate, Expand, Giant, Gold, Mandarin, Mining Village, Province, Silver, Torturer, Worker's Village, Young Witch, Wishing Well
Again bad player gets giant, good player gets torturer and ignores giant. Good player wins.
Provinces / Estates - Copper, Curse, Duchy, Estate, Gear, Giant, Gold, Laboratory, Mint, Page, Peasant, Province, Ranger, Scavenger, Silver, Worker's Village, Herbalist
GIant is ignorable again as one gets quickly champion to moat and gold for economy. I disagree bit with players opening as page-gear looks best because you will likely mint 5 coppers with gear on turn 3-4.
Provinces / Estates - Copper, Curse, Duchy, Estate, Fool's Gold, Giant, Gold, Herbalist, Jester, Laboratory, Moneylender, Noble Brigand, Oracle, Province, Silver, Swamp Hag, Torturer, Raid
Log Viewer Kingdom
First game where player that buys giant and opponent doesn't win. But its because opponent plays moneylender-oracle bm. Torturer or swamp-hag bm here should crush giant.
Provinces / Estates - Advisor, Copper, Curse, Duchy, Estate, Festival, Gear, Giant, Gold, Golem, Potion, Province, Scheme, Scrying Pool, Silk Road, Silver, Stash, Thief, Summon
First game where its clear to get giant, as you could find card to trash with scrying pool, as well as main source of coins and use festival+gear to keep copper+other junk from deck. 1 point for giant
Provinces / Estates - Caravan Guard, Copper, Coppersmith, Curse, Duchy, Estate, Explorer, Gear, Giant, Gold, Inheritance, Jester, Mining Village, Province, Raze, Silver, Urchin, Workshop, Plan
One game where giant doesn't help to spike inheritance as one gets that on turn 9 and buys a province. Here giant is skippable as jester is better and you will get inheritance faster with gear/silver opening+more gears to inherit villages then get workshop to gain estates. Even gear-bm should beat anything with giant here but former engine looks better than gear bm.
Provinces / Estates - Baker, Chancellor, Copper, Curse, Duchy, Estate, Giant, Gold, Grand Market, Mandarin, Mystic, Nomad Camp, Province, Royal Carriage, Scheme, Silver, Torturer, Seaway
Another game where player who gets giant but oponent doesn't loses. Here its relatively clunky torturer engine as only actions are from rc-scheme/grand market./torturer.
Colonies, Estates - Adventurer, Colony, Copper, Curse, Duchy, Duplicate, Estate, Giant, Gold, Journeyman, Militia, Mystic, Platinum, Province, Silver, Torturer, Transmogrify, Vault, Doctor
Again one player gets 2 vaults + torturer instead of messing with giant and wins.
Provinces / Estates - Adventurer, Armory, Bandit Camp, Copper, Curse, Duchy, Estate, Giant, Gold, Great Hall, Hunting Grounds, Merchant Guild, Province, Scout, Silver, Wine Merchant, Doctor
Here hunting grounds bm beats giant player. There is a mechant guild engine possible if you overpay doctor and giant has no place there.
So based on these games one could say that giant is rarely useful and if one ignores it completely would help you unless you are at least level 20 player.
Now to article itself and why its mostly first impressions that doesn't apply.
Part about using giant for early spiking 7-8 is first impression but it is wrong as it is rarely best move. It only works with 5/2 opening where giant could spike that reasonably early. Buying giant on turn 3-4 is most of times mistake as its only a copper on next shuffle and you spike it on shuffle after that. You could spike that with basically any reasonable draw cards in same time and you will have better deck than one giant+possibly weaker card from giant play.
As giant winning vs weak bm how weak one? Does it beat something more impressive than bureaucrat?
As giant in engines you made mistake in first sentence that giant is a decent payload. It isn't decent its terrible payload. You could always use gold as payload. Attack is quite weak because of that as you should pick giants and start playing them quite late where it won't matter as opponent could trash it with his engine. Trashing without inspect is weaker as it often just trashes silver. Argument that giant could beat opponent with bm is weak as in most boards its clear that one should do engine or there isn't engine possible and you should do bm. In engine mrrors that are most games giant would just lose you tempo.