This is a serious discussion. I mean, after I've seen how bitcoin (and other cryptos as well) got dumped badly after an irrelevant law that makes ICOs illegal. I can only imagine now what would happen If more countries do the same thing and It could get worst by make itself bitcoin illegal. Whether we like to admit it or not, most of people would sell everything they have once its made illegal, some may continue to fight the central banking but the sad reality is that as soon as people start making profits, they will dump it and move on.
It is true that governments in different countries can stop the spreading of the idea of bitcoin in their place. They have the power to ban bitcoin and make the usage of bitcoin punishable by law. The government has also the power to legalize bitcoin because it can help the economy of a certain country to grow more and develop. Also, if the idea of bitcoin is present in a certain country, there will be less poor people because of the capability of bitcoin to help people sustain their financial needs by earning their own money.