You just need to look on other sites that China banned- Google, Facebook, Youtube etc.
Are they are not still the most successful sites in their fields even with the china ban?
Correct. But the problem is that other governments might follow in China's footsteps and decide to ban crypto currencies. It is unthinkable for a normal democracy to ban Google, not so unthinkable to ban Bitcoin. They can cite a variety of reasons to do so.