They have rolled out a swipe to pay trial system in New Zealand for the Rugby World Cup. Its essentially the same thing, except it uses a chip off your credit card and not one in the cell phone.

Thats going to be Googles biggest competitor to this, the fact any wallet can operate the same way, and well you still need to take your wallet with you for various reasons e.g. carrying your oyster card in London for example.

Obviously win-win for the credit companies, I doubt they care which technology takes off.

Of interest the threshold is NZD$80 per transaction without authorization, which I guess is around USD$60, and I think it works even if you have PIN authorization set up e.g. it overrides the PIN at certain terminals.