But if it fails, how would trashing a supply card be a helpful thing for me, except maybe once in a while by purest coincidence?
Because you are in the lead and want to end on piles before your opponent's engine can catch up.
I get the general use for supply trashing. What I'm saying is, if I don't care about supply trashing enough to
purposely miss with my choice of Action card and opponent, then what are the odds I'll care about it
at all as a consolation prize for missing? That's the connection I'm not getting.
The strategy I'm trying to suggest is one that aims to gather VP quickly and eliminate piles. Ideally, you'd always name a card in your opponent's deck early on. If you hit, you get the direct benefits. If you miss, you still press the piles. Whether this card effectively pushes that strategy is up for question, but that's the intention of its design.
Ah, I see. So the idea is that you drain piles either way, but the "good way" is to get the cards you pull from the supply instead of merely trashing them?
In that case, I might suggest some sort of gaining mechanic for the "win" bonus, rather than the generic +1 Card, +1 Buy. Having an extra buy doesn't mean you'll use it, or even that you'll be able to use it. If you're trying to drain a pile costing $3 or more, this card only guarantees that you can do that if you miss your guess. More to the point, +buys go unused a LOT of the time, owing to general Dominion principle that one great thing is better than two good things. So unless you can get more than $8 to spend, you'd normally rather put the flat +$2 towards a better card than toward a second one. Loads of exceptions to this, of course, but if you put a gaining effect in there, you could
ensure that (1) supply piles are drained even if you guess right, and (2) you're
able to drain piles if you guess right.
Gainers are tough to balance, though, so it's a tricky proposition.