I can see how this could be a deal breaker for some.
Speaking only for myself, personally, I'm 42 years-old and have been a very slow adopter of smart phones in general. GrapheneOS let me feel like it's finally my phone and I've started using it more. Mostly as an mp3 player while exercising, and I've got an open source password manager that I've started using a lot. But I've never been comfortable with the idea of my phone replacing my wallet. I mean, sure it can do everything that my wallet can do but it's also susceptible to malware or attack and if I lose it then not only do I lose all of the data on my phone but I lose access to my identification and payment methods as well? That is a terrifying prospect to me. I don't like the idea of single points of failure. Losing my wallet would ruin my day. Losing my phone would suck but nothing catastrophic would happen. For most people losing both would be a nightmare scenario.
But I don't even do online banking on my phone. I probably could. I choose not to.