There is no issue from graphenes side really, Google wallet doesn’t work because obviously Google doesn’t allow it to. nfc payments always worked if you are lucky enough to be with a bank that does it through the bank app itself, there’s nothing intrinsic about the os that stops them. There are a few of those online banks/money apps offering this now, some people have said PayPal works? And various other services. If you Google a bit you should find some suggestions. I don’t think the convenience is worth the privacy invasion of mobile payments, it defeats the whole point of having a secure os tbh.