I think it is only illegal if there is a law that makes unregulated market illegal. The crypto market in my country is still largely unregulated but the people are free to use and trade any cryptocurrency from both local and international exchanges. Some countries have already imposed their own regulation to curbe some illegal activities and protect their people financially.
The whole notion of protecting the people by the government is just a big fat lie, if they want to curb the scammers they can very well do that, the people who invest in bitcoin and the entire market know what they are doing, the government must curb alternative investment platforms in the name of bitcoin to protect its users and not the market altogether claiming that they are protecting them which is a bull shit argument to make.