Not all crypto currencies are equal. Some crypto perform various functions similar to network packets or Internet data. If you understand an IP packet has different sections then you can see how Etherum might have different crypto layer protocols.
Some crypto such as Helium are concerned with actual Internet services.
Crypto is more about developing new communications protocol than simply money.
Governments have focused on values and the security to replace their existing money products.
Block chain is also how NSA essentially issues and implemented Secure Keying materiel for COMSEC.
So many examples....
China has tried to ban Crypto currency about 4 or 5 times and has failed every single time. Its basically impossible to ban it. You’d have to shut down the entire internet.
One of the biggest exchanges is KuCoin. That is extremely decentralized and is owned by no one. There is nobody for the US to sanction or arrest. There are no servers in the US to shut down. KuCoin requires no KYC (Know Your Customer....ie identification). Anybody can trade there. The same is true of other decentralized exchanges. They can’t be shut down by any national authority either. Anybody can buy and sell and trade crypto on those decentralized exchanges.