> because the quality and coins

a popular exchange like binance offers hundreds of coins and certainly all of the major ones, and probably more than any bank can offer. If you need one that is not in their list then you must be looking at a very weird merchant. i agree that crypto wallets are still cumbersome to use for average users, but finding and signing up to exchanges is easy.

> I can transfer money through my phone app (or online banking if I prefer) to any other UK bank account

does it work equally fast and cheap when you send money to japan or australia?