I think it is used by some people there, government can't ban Bitcoin as long as there is Internet connection accessibility.
In North Korea it isn't a democratic government, but dictatorship. Use of internet is highly restricted, only a small majority have access to internet. There are some rumors about the North Korean government's interest in bitcoin
1. It is rumored that the WannaCry ransomware is linked to NK.
2. It is rumored that state backed bitcoin mining operations are going on in NK.
3. It is rumored that state backed hackers stole bitcoin from South Korean exchanges.