Bitcoin is a digital currency that circulates freely, without any control or supervision from banks, governments, or anyone else. In contrast, bitcoin relies solely on cryptography and software between computers.
what if the government closes or does not allow the exchange of Bitcoin or cryptocurrencies with the official currency in each country?

This is the same question for me. How come bitcoin crash, can people or group of people with very huge amount of crypto crash the market? Therefore cryptocurrency is not a very good platform to hedge your investment.