There is no real gain in convenience compared to a Starbucks Card or cash, and you still have a paper receipt involved in the transaction. I'm having a hard time seeing how this is a step forward.

PizzaHut did a similar thing a while back:

http://www.techcrunch.com/2009/08/01/pizza-huts-delicious-ip...

Except it is more geared at remotely ordering a pizza to be delivered.