Most of well known countries and has a good economical status legalized and regulates not only just bitcoin but crypto currencies as a whole, It is because most of the developers and supporters of digital currencies comes from those countries. I can see that adaptation of other countries lies on how those big countries support cryptos. No wonder in the coming years bitcoin will be more legal and regulated without any restrictions and sooner become one of the major currency circulating around the world.
If the world acceptance as I see it is quite wider there's no doubt the it is the world currency to be and become more popular than dollars and euro, because bitcoin has no boundaries and the cryptocurrency, as long as the there is Internet connectivity it can be reached by anyone.