I don't think so. All you're phone is doing is authenticating you are you and your credit card account information, although its not really sending out any credit card information. This is what makes it so great and secure. If they had an iPod Touch with NFC and the fingerprint reader you could probably use it as well for Pay.
I don't know many that use solely full-screen apps. I'm not really a fan of them to be honest. I actually pisses me off that the green button on a window makes your window go full-screen instead of changing the size of it. It was one of the features I reported to Apple to put back the way it was. There was nothing wrong with the Mavericks way of making an app go full-screen.