Well, they did not kill yuan. And that won't happen.
China is one of the most powerful countries that has ever existed, they need to create regulations over everything (and their kind of government is very succesfull)
So yes, if it happened, then it means that it was a good decision after all..
China is the furiest among them, claiming cryptocurrencies kill yuan and threat Chinese economy. So they are going to strengthen the regulations and ban everything connected to cryptocurrencies