I am one of them. I pay with BTC wherever I can. And I prefer to receive BTC for my side gig (for 12 years).
But I still need a bank account for the many things I can't pay with BTC.
On many occasions where I pay with BTC, they tell me I'm the first after offering that service for two years. In other places the devices for receiving BTC is not charged or doesn't work for some other reason. They don't even care because it's only once a month that somebody wants to pay with BTC.
If we want a BTC standard, we have to actually use it, and not just speculate that one day it will miraculously happen.
Most merchants who accept BTC convert to FIAT. That's not ideal, but still much better than not accepting at all. And they need the on/off-ramps.