I would say that also we (at least in upper middle class USA) have been conditioned to not feel comfortable with self-custody.

Like I have some amount of bitcoin and a small amount of precious metals, and outside of that, most of my assets are in financial institutions. Before I had bitcoin, basically everything I had of value was in a bank or brokerage account. It's frankly weird as hell being in physical custody of precious metals, especially when I think about / hear about robberies. It's also weird having bitcoin off an exchange - I prefer it, but it's still weird thinking that I could screw up and lose it without insurance or protection. (I'm particularly paranoid I suppose because as a kid I would always lose my coats and stuff somehow, but now I'm a lot more careful)