Google Wallet usage has doubled since allowing all credit and debit cards
working on its own mobile payment system. But the problem with the handset was resolved, and Google said that it was positive on the future of the virtual wallet. Google has provided its partners with an API that allows them to put a button on their web site allowing customers an easy way to have their card "saved" in Google Wallet. After tapping the button, the customer signs in to his Google account and the card is added immediately. There is no need to actually type your credit card number on the screen.
The mobile payment business is a competitive field and besides Sprint, competition for Google Wallet also comes from Isis, which is the service offered by Verizon, AT&T and T-Mobile expected tro launch soon.. As more Android models launch with NFC on board, mobile payment is a feature that could rise sharply in popularity over the next few years. If usage of Google Wallet can double in a matter of weeks, the numbers could be staggering in a couple of years.
source: Google via AndroidCentral