Many countries seen cryptocurrency as a threat in their current economy. Maybe this is due to many issues cryptocurrency suffering. Many has already become a victim of the scams and huge hacking issues.
Well i do not believe that there are so many countries that ban the use of cryptocurrency. I believe that there are only quite few of them and those countries have problems in dealing with national security threat. As we all know that the cryptocurrency has its trademark as anonymity so it could be difficult to trace if transactions being done for smuggling weapons will be done using cryptocurrency system. However, in different countries cryptocurrency is doing good and local exchanges had done KYC to track those people who use heavy or having huge transactions.