The value of Bitcoin affects the interests of the government. Users who use Bitcoin for illegal purposes will be banned from the operation and are responsible for the country.
I think that makes the country afraid, so it doesn't use Cryptocurrency, because they feel that if citizens use Crypto, the state or the government will not be able to control it.
The main reason for a country that does not accept Bitcoin and Cryptocurrency is, because Cryptocurrency is decentralized, or cannot be controlled, cannot be regulated by a country.