I know the common joke is that Google made a mess of their messaging apps. I 100% am not clear what the correct app is to be able to do tap to pay from my phone. Kind of comical how hard that is to figure out.
You only run the "Wallet" app UI if you want to mess with payment details, and even then it's integrated with all the other account payment stuff. So if you tried to sign up for more Drive space or ad-free youtube or whatever you've already done it. And in the worst case if you tap and you don't have it set up, it pops up automatically and prompts you.
Your complaint seems to be limited to the fact that they used an app name ("GPay") for something other than NFC payments. But... so what?