I do it with UFT/S characters, hoping to have the funds to buy them someday, or hoping that the owner will look at my profile and see a character they'd like to trade theirs for :') Though that's only on my trade account.
On my main account, I fave characters I love for their art, background, concept, etc.... as well as codes I'd like to use. Sure, I'd love to own some of them, but I don't see my faves as a wishlist.