We really need to move away from the idea that a user having control over his/her device is insecure.

I can use online banking and paypal with windows logged in as administrator or GNU/Linux logged in as root[0], why shouldn’t I be able to use google wallet pay wallet with root?

[0] yes I know you shouldn’t log in as root, but that doesn’t change that you can do it.

“why shouldn’t I be able to use google wallet pay wallet with root?” Because little innocent Google won’t be able to build their advertising profile of you. Can’t have that!