I don't think there is much appetite for something like one global currency. Governments like the idea of having their own currency they can shape the way they want, which isn't possible if they use Bitcoin.

Gold was somewhat of a global currency ages ago, but even at that point there were different forms of money locally. I am in favor of different forms of money because it gives you the option to choose the best one for you.

The great thing about crypto is that we have so many alternatives, that in case one goes down for whatever reason, we have another one ready. More power to the people.