I can speak as to former USSR countries. Our legal systems can be classified as roman-german. That is why we can apply basic principle of law, which states "all limits must be named in a rule of law". In case of cryptocurrencies, if regulators haven't named specifically an object of tax law they can not apply tax rules. For example, in Civil Code of Russian Federation, Ukraine, Belarus there is no definition of cryptocurrencies and there is no reference that other acts can classify new objects of law. Hence, cryptocurrencies are not "things" or "IP ocjects".