Google Play Services ruins dream of this. I've noticed that automotive digital keys don't work with Graphine OS due to how Google Wallet works.
Or most banks, government apps, and so on. Which all require an app to login, rather than support any open and actually secure standard.
I thought I would miss google wallet but after 2 years of using graphene I came to the conclusion that it is easy to live without it.
A non problem imho.
I think a Linux phone probably appeals to the same kind of person who prefers real keys over digital ones.