The main reason for prohibitions is very simple. Transfers in a currency different from the national one, lead to poor economic performance, including GDP (one of the main indicators). This way, it is easier to launder money or transfer funds outside the country. Neither banks nor payment processors will get their interest.
McCall Robinson a manager of Merchant Accounts, believes that most countries prohibit Bitcoin because it cannot be regulated and he said that. "Many governments do not like the very idea that there is another form of currency that they are not able to control. The supervision takes place on the Internet. Some countries consider it as danger to their society and government.
Cryptocurrencies have also negative side and it is the reason why there are some countries that ban cryptocurrencies. The anonymity of the cryptocurrencies are using by some greedy people and bad person for their own satisfaction.
That's the reason mate why the government of some countries ban Cryptocurrency because of the negative impact and it is used by other people in bad ways,and also they want to protect their citizens that's why they not introduce it so that they are not victimized by a scam using Crypto transaction.