I feel the best way to use cryptocurrency for buying and selling is within the crypto ecosystem. It will be pretty hard to get government approve the use of cryptocurrency allover their countries unrestricted. Even if they do they will eventually use it as bargaining tool to get what they want from developers. If you refuse to cooperate they will kick you out of their countries.
This happens, every government is corrupt. From my understanding there are governments that want to grow on the digital platform. Those countries have already adopted cryptocurrency as well the blockchain technology. Globally online services with bitcoin acceptance have increased a lot. The same hasn't increased on physical stores where we do majority of the shopping. In the future this could happen as the present generation is almost adoptive to technology from birth.