So don't do that?
I think I still have a 'regular bank' account open, but I don't use it at all. Salary goes into Monzo, and payments go out. It's the only debit card in my wallet and that I use.
I didn't switch wholesale because I'm not fully convinced. I feel these new banks and bank-like offers will for some time search for a right fit and may change or disappear in the next few years.
Also, no-fees-abroad is a great feature, but perhaps not the 10x to spur (my) wholesale adoption.
Maybe I'm just not an early adopter (although I use them abroad, so in a way, I am).