I was thinking the same thing.  This really isn't rocket science. Any payment system that works off of a barcode could work on the Band.  For that matter, if only the Band had NFC, it would support Google Wallet or SoftCard.  Using a barcode system for payment seems very open to fraud.  On the other hand, Google Wallet's system of requiring a PIN, being nearby and inserting a proxy credit card in between makes a lot more sense.