Sorry to burst your bubble, but if a government wants to prevent you from using a cryptocurrency it has many tools at its disposal. Firstly, they control the ground upon which you stand. If they don't like that you are using crypto, they will simply arrest you and charge you with a newly-formed crime like 'digital tax evasion'. Secondly, if they can't find who is using crypto, they have the power to shut down the Internet or simply censor requests. No ISP has the military force to prevent a government from walking through the door and cutting the cable.

Point is, as long as you are on their turf, you will follow their rules. Unless you want to make your own rules, in which case you will have to fight the government, become the government, and realize that having no control over a currency being used in your turf can be really bad for you and your citizens. You have no control over its value to at least try keep the economy stable, and they will have nowhere to turn in event of a financial crime or scam. No courts, no recourse, no trust.