Will anyone use this? Not anytime soon. Right now they are integrated with one phone on one network with one credit card. (Nexus S on Sprint with a Citi Mastercard). The number of people that have that is pretty small, but then they also have to use it at a vendor which supports it. Google did a great job with this, partnering with Paypass so there is an existing vendor base already http://www.google.com/wallet/where-it-works.html… that being said, it just seems too complicated at the moment, and not a huge value add. I love Paypass already, and it's not that hard for me to knock my wallet onto the device. This doesn't really make it that much better.
We're really a couple of years off from broad-based adoption of NFC. The other thing is that Apple has a huge say in adoption. Some say the iPhone 5 won't have NFC. Even if it does, there is no guarantee that Apple will support Google Wallet right off the bat (See: Google voice - yes it's supported now but still crippled and it took a LONG time).