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?
The government not being able to impose taxes on cryptocurrency is a big deal. Taxes are mainly the source of income of a state/country. A lot of people earn huge amounts of money through crypto which could have a great impact on the amount of taxes the government may receive. Some country's ban cryptocurrency to avoid tax evaders to become more rampant. It is quite easy to convert fiat to bitcoin. And once fiat has been converted to bitcoin, the government has no power over the individual's money anymore.