Hey Evil Chris,
Only billing downside is that it's a debit card, so the surfer needs to have money on the card, rather than just be under their credit limit.
I don't think it will replace billing on credit cards, but it certainly is an excellent alternative billing method which will allow us to take more transactions with less risk.
It's also a great way to get paid by your sponsor
Go to
http://www.flashcash.com to get your card and try it out.