It makes a whole lot of sense that Bitcoin isn't accepted a a major Currency because the people inside the world don't really know about it yet.
Most of the People think that the next digital currency will be backed by gold or something that the Chinese will integrate in their Currency and people will lose their money because USD isn't "Valuable" anymore.

If Bitcoin was well known then the people who decide a what is Currency will be have to list it as a Currency whether it's underground or not.