Android 4.4 brings a major change to NFC payments that could finally be the kick in the butt that Google Wallet needs. Kit Kat brings support for Host Card Emulation (HCE), which means any Android NFC device could be used for mobile payments without needing access to a secure element. With HCE any app can emulate an ISO/IEC 7816 smart card that use the contactless ISO/IEC 14443-4 (ISO-DEP) protocol for transmission.
What does all of this mean in a nutshell? This means it can work on any device on any mobile carrier. Not only that, third party apps can manage payment information in the cloud or on the device. Of course, devices will need Android 4.4 for this to work, and it remains to be seen how long it will take for most of the popular devices to get the update. It will take some time, but it could just be what the doctor ordered for Google Wallet to finally succeed.
source: Android Developers