The only thing I don't like about giving out coins is that most of the people we hand out cards to are not going to redeem them or even figure out how to.
I think there was talk about the ability to check the numbers on the cards to see if they are used or not, that way refunds from donations can be given. I think, I'm too lazy to search.
I dig the idea behind your card, just a straight up card for info. I think the back of the card is actually perfect, and I would just take that front of the card and organize the words differently rather than have the keywords kind of spread across. If that text had a more uniform look, I think that is the only thing throwing me off personally as far as the card design.