in my opinion, why is bitcoin never a global currency, because every country already has its own currency, if you want to put bitcoin in it, of course there is a process that involves the entire country. If this is the case I find it difficult to make bitcoin a global currency ... !!
Added to that, not all countries are in favor in cryptocurrency, yes they might want crypto, but just means as payment solution, alternative money transfer for fast remitting or money, can be a form of investment but not as a global currency, although I would love too, still we know that it can't happen as of the moment.