Exactly. I can rent some storefront right now and set up a fake card swiper. Maybe the barrier of entry for this kind of thing is lower... but is it lower than creating a web page and stealing credit card numbers?

The beauty of credit cards is that you're not responsible for fraud. I know that when I go to a restaurant the server could easily take a quick cell camera shot of my card, but I accept that risk because I know that I monitor my card activity and that I can recover that money if it does happen. The same applies here.

barrier to entry is much smaller, you don't need to piggy back on a legit business or have to play a spy to install a skimmer at the bank.

All you need is a taxi, and iPhone, and you can go around town collecting credit card numbers.

And unlike websites, there is no paper trail to link you to the scam.

Your iPhone leaves a data trail, at the provider, at wifi spots, at bluetooth sensors. Now someone who is technically adept could muddy that trail considerably. But the basic forensic evidence is still there. And remember, for the most part criminals are human, and make human mistakes; they will do a transaction in full view of a security camera, or something equally dumb. It's no better and not much worse than the systems we have now.