I have 2-3 articles and an article series planned for the first half of this year. This one is about Trade, an event which seems to be somewhat ignored and shouldn't be. This is the only one planned broadly about a card or event as this type of article tends to fall rather low on the usefulness scale.
Silver is not a good card. Trade gives you Silver. Trade is a good event. Oops.
Let’s try this again. Coppers and Estates are bad cards. Trade gets rid of them. Trade is a good event. Okay, that’s better.
And that is what it comes down to: Silver is better than other assorted garbage. Way better. Like worth $5 and a buy better to have 2 Silvers over 2 Otherassortedgarbages.
The FunctionWith $5 in play and one or two cards in hand, Trade gives you the option to replace those cards with Silver. This is good when those cards are worse than Silver for your deck, so Estates and Coppers and if your opponent is being nasty Curses and Ruins also. Now, while this is not pure deck thinning, it does significantly increase the power of one's deck without adding any additional cards, and so if it is to be done, should be done early and often.
While a comparison to any card will be imprecise, the most direct and relevant comparison is probably Jack of all Trades. Like Jack, Trade allows a person to both gain Silver and rid oneself of junk cards. Now, Trade costs $5 while Jack costs $4, and its advantages correspond to this price difference: as well as being able to trash Copper, buying Trade to trash even just one card puts the Silver in your deck a shuffle earlier than Jack would and does not leave an additional action card to draw - make it two cards in hand and it is a two shuffle advantage.
The ConditionsSince Silver is almost always better than the assorted garbage listed above, if Trade is the only way to get rid of that junk then it is more often than not the correct choice to Trade if one has two cards to turn into Silver. There will be some exceptions such as forgoing Trade for a power card such as Wharf which itself would lead to more effective Trade buys. In this case it will be rare that an engine which does not produce extra buys will be able to keep up with a Trade based money strategy (there is a notable and important exception that will be detailed more in a different article I have planned - presence of a discard attack).
If real (and strong) deck thinning is available then you need to decide if Silver is better than nothing, as Trade provides the former and whatever thinner the latter. In many engine strategies, this will not be the case until after the starting cards have already been cleared, although if before then, Trade is there to make that happen and is better than buying Silver or even Gold: if one Trades two junk cards one is adding between $2 and $4 of treasure payload while not increasing the size of one’s deck as buying one of these treasures would. In money strategies, on the other hand, Silver is nearly always better than nothing (same exception) and so Trade is most often preferable to investing in the thinner.
The SpecialtyAs alluded to above, Trade is one of the best money enablers around, and if Trade and no additional gains are present, one should think really hard before not pursuing a money strategy.
In the presence of draw, terminal or otherwise, Trade allows for lightning fast and extremely consistent money decks. Even a mediocre terminal draw money strategy such as Smithy can be improved to taking in 5 Provinces and 1 or 2 Duchies in 13 turns fairly consistently with no attacks coming in. A strong one such as Gear can make 6 Provinces in 12 turns a near certainty under the same conditions. Leaving some Copper in the deck is fine and looking to buy Trade 3 or 4 times is often ideal. While these cards usually lead to otherwise fast enough games that multi-gain engines should be able to overcome this, it is unlikely that the same could be said single-gain ones.
Additionally, such a deck will also be very resistant to junking attacks as one would might guess with the comparison to Jack. If better (and/or cheaper) draw is available than the junking attack, skipping the junking attack entirely to focus on speed while using a few additional Trade buys to turn the incoming junk into Silver when possible is likely to outrace the weaker or slower drawing junking player to Provinces. If the junking attack is the best draw, then you are buying it and just as with other draw, Trade to clean up the deck turns it into a force to be reckoned with.
Additional ThoughtsHere is a sample game (log) illustrating this speed with another strong money enabler, Courtyard. Here it takes me 12 turns to get to 5 Provinces and 1 Duchy.
I mention Trade specifically in the context of draw because this is the easiest and most consistent way to get to both $5 and 2 cards in hand; it is possible, if significantly more difficult, to reach these conditions otherwise, and Trade is a good option in these situations also for the same reasons as with draw, as can be seen in
this game from Qvist (video).