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.
That is a sad reality. But I do not see bitcoin stopping from now. There is no stopping bitcoin. Even if it is declared illegal by some countries, bitcoin still becomes unaffected and value continues to rise. China once banned btc but they made a counterdecision to reverse it and make it legal.