This card is under-rated and I believe that this article could be expanded upon/improved. Here are my main considerations. I'm just going to go sequentially through the article and pose my arguments.
Well What is it
This section is fine as is. The last sentence is a bit out of place.
In Big Money strategies, buying Masterpiece for $6 or more can sometimes be superior to Gold, but most engines will sputter and die with that many non-drawing cards in your deck.
In most cases buying a Masterpiece at $6 or more is superior than Gold. More on this later. Masterpiece is not meant to be an Engine card. It's use in engines is mostly irrelevant. In engines, the raw power of Gold in a single card is much more useful than the influx of Silver.
So How Do I Use It
The first paragraph is not emphasized enough. That first Gold is extremely helpful. Subsequent $6 should most often be Masterpiece buys. For Masterpiece to truly shine you need more than just one Masterpiece buy. You are looking to absolutely flood your deck with Silver allowing you to do a few things extremely well.
1.) Green earlier
2.) Prevent choking
What does this mean in the context of deck construction? Let's take a theoretical example. You have 18 cards in deck including a Smithy meaning you get 3 hands before your next reshuffle. In your deck you hand 7x Copper, 3x Estate, 5xSilver, 1x Gold, 1x Masterpiece, 1x Smithy. This is a total of $21 gold over 18 cards giving you a density of $1.16/Card (Province buying is $1.6/Card). With your $21 over 3 hands you buy 3 Masterpieces overpaying for each one resulting in gaining 3 Masterpieces and 12 Silver. Let's recalculate average money density. You have $48 money in 33 Cards giving you $1.45/Card. Imagine you had bought 3 Gold instead of Masterpiece you would be at $30/21 Cards = $1.43/Card.
So by going Masterpiece over Gold you are keeping your average money density about the same but your buffer capacity (I teach orgo lab and just graded a ton of reports with a phosphate buffer system, had to put in chemistry blurb) is much better. You deck size is 33 as opposed to 21. This means that as you are less prone to choking on green. You can green earlier on Duchies and use the extra VP to outlast you Gold gaining opponent in the long run.
So back to constructing you deck. The above was an ideal hypothetical example. In practice I have found it to be most useful to flood the deck when you deck is in peak condition. This usually happens after the 2nd reshuffle. So you should look for these Masterpiece buys starting at Turn 5 and onward. After you have gotten about 2 or 3 Masterpiece buys you are ready for greening. There is wiggle room on deciding whether $8 should be Province or Masterpiece + 5x Silver. My advice for this is to ask yourself the following: Will you make it completely through your deck again? If yes, go for the Silver, if no, go for the Province. When your deck is medium sized. You can get Duchies on $5. If you're going through your deck again (think of the amount of VP left) you probably want $6-7 to be Masterpiece.
On the topic of TfB and Masterpiece. I would say that this is a nombo. Masterpiece floods your deck with Silver making it unlikely that said TfB will hit that Masterpiece which is the ideal Target. Silver is a mediocre card for almost all TfB that could conceivably be used.
Masterpiece also excels in slogs.
Cursers and Looters will make it much harder for your opponent to line up enough Silvers
I disagree with this. Cursers and Looters are cause to go for Masterpiece. They serve to stall your deck by increasing your deck size and thus lowering your average money density. The presence of Masterpiece allows you to create a buffer in which each individual Curse or Ruin has less of an effect on you average money density. This is assuming that using trashing as a means to control Curses is minimal and that engine potential is low anyways.
Here are a few sample games that I have played recently using Masterpiece to great effect.
This game shows the power of Masterpiece to overcome cursing from Witch.
Hunting Grounds/Masterpiece has 18 Silver after turn 8!
This game shows province buying power in a Swindler/IGG game.
In a game with Pirate ship and no reliable +Coin, Masterpiece easily overwhelms the attack.