(If not, why not?)
(Imho, it would make sense if only the state can pay ransoms)
Instead, you would pay (exhorbitant) consulting fees to a foreign-based "offensive security" entity, and most of the time get some sort of security report that says if you'd simply plug this and that holes, your systems would now be reasonably safe.
Yes, that's why cryptocurrencies are a gift from heaven for these hacker groups.
Therefore, even if paying ransom money (somehow) must be legal, maybe it should be illegal to use crypto for it. You don't want to make it too easy to run this type of criminal business.
You go on some Russian crime forum and find a plenty of people offering to process bank transfers like these for some percentage of the money. As these particular payments would be somewhat consensual, you wouldn’t even have to worry about the funds getting frozen on the way.