I thought it was to prevent abuses if Gold were swindled into a Farmland (what a nightmare...) and forcing the attacked player to remodel a card. But it's true it seemed me weird, why not on gain, because remodeling several $4 into farmlands this way would have been uncommon... before Fortress !
I wish the on-gain part were : "When you gain this and didn't gain another farmland immediately, you may trash a card from your hand. If you do, gain a card costing up to $2 more than the trashed card".
And then, two another ones :
Why did I hide the name of card, which is Mint ? Don't care. But I have something to tell you ?
I'm sorry, I'm soooo sorry !!! And yes I love oldies much more than actual video games ! (Final Fantasy up to 10 :p <3)