They may ban it, but are they doing, or can they do, anything to enforce said ban?

If enforcement isn't possible, can it be considered controlled?

China has 'banned' Bitcoin n times. That in itself tells me how well, or otherwise, it can be controlled.

Monero is crypto-non-grata in many countries. That just means obtaining it requires visiting slightly dirtier and slightly darker alleyways.

So just like every other crime, then?

Depends how it's banned.

Some countries block exchanges within their jurisdiction from offering Monero, for example, but it can still get obtained via other means. Peer to peer, offshore exchanges, decentralised exchanges.

Owning it isn't a crime.

> Owning it isn't a crime.

Not sure if you meant "in general". Whatever the government decides is a crime, is a crime.

Slavery is banned. You can't own people. For some crimes countries like having extraterritorial jurisdiction, too. E.g. FGM "tourism" and child sexual exploitation. It's not just warcrimes that are extraterritorial.

I'm not equating these, certainly not morally. I'm saying that saying "outside the control of government" and "can't be banned" is either false, or applies to any other crime too.

And if it applies to all laws, then that's basically the sovereign citizen theory of laws; people getting the legal consequences for their actions all while saying "you can't do this", where "they" demonstrably can.