It is possible that crypto currency may or must have been banned in some countries. It is also be possible that in some countries it seen as illegal or may be regulated, especially some developing and under developed countries just for the sake of protecting the citizens of such countries.
But one thing in sure, in as much as some developed countries have embraced the innovation by accepting it to be legal and used as a legal tender for goods and services, the rest of the world would eventually accept it.

The world has become a global village where businesses thrive between countries of the nations and with time, this factor alone would aid the acceptability of crypto by so many countries who are currently seeing it as illegal.