card.io is pretty cool—I wasn't aware of it until now.<p>I’m just shocked at how poor the security of the entire consumer finance system is, if you can accept payment just by taking a photo of someone’s card. I wouldn’t be surprised if professional credit card fraudsters had implemented this technology years ago (except with covert cameras).<p>A sincere question: what would stop you from photocopying someone’s card and using it to buy goods with this system? At least with Square you need a magnetic barcode, which might act as a very mild deterrent.<p>EDIT: FYI, I live in Europe, where we’ve had Chip & PIN-verified PoS transactions for a while now. Still not the best security, but at least it’s no longer trivial.