Since this is a cantrip, one strategy would be to piledrive it and then throw them in a megaturn. If you managed to get 8, you could grab all 8 Provinces in one go, with some Duchies to spare.
If there's a decent support card around, and your opponent is doing the same, you only need 5 or 6. Assuming the two of you empty this pile, the first person to luck out can empty the Duchies and then finish off the support card pile.
On the other hand, they aren't that great until you have 5 or more in play. If you get 4 out, you can turn a single $5 card into two $4 cards, which is like a reverse double-Feast. You could of course get 8 $4 cards this way, but if they were good, why didn't you just start with those? Cities are in a similar position, but they are at least Villages until they power up and you take your mega-turn.
Maybe make this a Peddler variant (I know, missed the challenge) and add $1 to them? I know that the Peddler effect is priced at $4, but I feel like they should do something else at least.