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.
I think the government in the country hardly be able to completely prohibit Bitcoin trading, because the majority of individuals trading BTC through the trading platform, not direct transactions. The BTC trading floors are located overseas, not in the management of that national government. Because simple BTC does not depend on any currency, any country should ban it is difficult to do, unless the BTC no longer exists.
They cannot stop it because they cannot control the minds of many people unless they will banned it in their country just like Korea will do. Korea believes that bitcoin is just deceiving us from transacting money over nothing that is why they decided to banned it as well. But here in our country they don't have plan to ban it in fact they will legalize it here.