Why does Google Wallet depend not only on the Phone but the Carrier as well?

I'm trying to use Google Wallet on a Moto X at Duane Reed. I'm under the impression that this *should* work. However, when I browsed the help file for Wallet, it lists a number of Moto-X compatible devices, but they also list the cellular service. * What is the technological, or vendor relationship that is needed in order to Google wallet work with Moto-X with T-Mobile? * Why is there a dependency outside of the actual phone? Is the cellular operator working with Google, sharing my PII, and monitoring my transactions? My goal is to understand the extent the cellular operator is monitoring my on-device actions, and purchases.