Lot of countries do not allow to use crypto currencies and they discourage using them. However as far as I feel, trading with crypto is not that harmful for the economy of the country. As an example, if a person has Eth and someone from another country needs to buy Eth, that buyer needs to pay the seller in terms of dollars. Then that seller needs to convert that Dollars to his native currency which means it creates a the demand for the native currency and increase the value of the currency. May be the government is unable to add a tax on such transactions but it is beneficial for the currency used in seller's country.
What do you think about that?
One of the reason why they not allowed it is decentralized which no one can control or manipulate it even a government. Most of the government do not support because it is tax free and if everybody in a country use it the government will never get a tax again. Lastly, I also think that the government will not allowed simply because they it is a scam even though it is not.