You need some physical locations. Even for checks, unless the BoA/Citibank/whatever ATM is going to accept check deposits for my hypothetical treasury acct, I’m not going to want to take cell phone pics of every check I get or whatever. Those apps can be real buggy, IME.
But yeah I do get the impulse to leapfrog and do an all-digital public bank. I think there’s a solution somewhere in the middle with a mostly-digital public bank or something to that effect.