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 ... !!
I think that means Bitcoin as a global currency like a dollar (widely used). This is not yet possible, because global acceptance by all the countries is needed, and this is not possible, because many countries see Bitcoin as a threat to their economy