Pretend that all the fiat money in the world is gone and the whole world is only using Bitcoin. Ignore scalability issues for this scenario.
Well, if in this case we ignore scalability, I think this will only end the same as banknotes in general, it might only be different in a usage system that might be more prectic and sophisticated. well, scalability is an advantage of using bitcoin, I think in this case bitcoin will only end in unsustainable development