Earlier quoted context omitted.
You don't need a specific ban. Just even the playing field for traditional finance. Either make cryptocurrencies follow normal banking/financial laws or make laws for traditional finance more liberal. Cryptocurrencies and especially PoW based ones are a terrible, slow, inefficient and vulnerable technology which wouldn't survive a day of fair competition.
What is “fair competition”? Can you define it?
There are a lot of regulatory burden when trying to make a financial service. KYC, anti money laundering, reporting, privacy, data storage etc. There is basically none (that is enforced anyway) with crypto. That's the only reason it got traction. The technology is terrible. It's hard to come up with something more inefficient, expensive and hard to use. The one and only reason it's used for anything is that it evades regulatory burden.
It's literally "let's burn a lot of coal to run our steam powered car because steam powered cars are not subject to traffic laws" kind of situation. Fix and enforce the law and the steam car disappears. The same will happen to cryptocurrency.