I am sure the state must have a reason why the government forbids the use of crypto. Not just taxes  itself, there may be some things that the state fears. They are: crypto can be hacked, used for crime, the risk is very high for investors, and no one is responsible if there is fraud.
Perhaps the most fundamental reason is the fear of the country regarding volatility and uncertainty of the crypto currency.
The bank also feels excluded due to transactions without going through the bank, so that it can disrupt the country's income and economy.