This could be killer if it lets you do person-to-person money transfers like PayPal. If my buddy can pay me back for the movie tickets I bought him earlier with his iPhone and have it go straight to my bank account, I would definitely use it. Obviously there are security and other barriers to overcome but it's not an impossible problem. You don't really need the hardware for this type of thing though.
You are going to carry around an acorn like device for your iphone so you can swipe your buddy's credit card after you lend him money? And if he has his credit card why wouldn't he just pay for his tickets using the card?
I don't think this product is targeted at peer to peer money transfers for individuals. It's for businesses who want to charge customers. The pizza delivery guy or the taxi driver who, today, copies down your credit card number or "calls it in" for example.
I only use my credit card as a payment method. Most online shops don't accept anything but credit card, and sometimes I just don't have enough cash with me and don't want to bother walking to the closest ATM.
Credit cards allow you to loan money but I think that's ridiculous. I don't want to have a debt every time I buy something, I just want to pay immediately, with the money I already have, not with money that I don't have.
