A couple times I've had Wallet as my top battery user, even though I've yet to actually use Wallet on my N5. A reboot seems to fix it for a few days...
I was also seeing the same. I've done a hard reset (for other reasons) and have yet to see this come back. If it does I'll most likely just disable it as I don't use it too much anyway.
I use google wallet regularly and have for the last three days and have not seen this. I do have the location setting in the app off. I wonder if location service is running.