They lose nothing. Its their prerogative to initiate use of crypto but since they do not want to associate their people with it means they are not interested.
I don't expect anyone could reply in this manner or are you saying Bitcoin does not have any benefits? If it does, then both the government and their citizens have a thing or more to lose. What drives the agenda of some of them for banning Bitcoin is the decentralization of the coin, they want to overshadow every transaction thereby depriving everyone of their privacies. I will be opening a thread on this subject, this will help further in broadcasting what both parties would lose to more audience.
Bitcoin has the benefits that make it alive today, but just because it's useful to us doesn't mean it will be useful to the Chinese government. The answer is pretty negative but nothing wrong, China doesn't like bitcoin and they probably don't need bitcoin either. They have become superpower without the help of bitcoin, we should accept the fact. But bitcoin never needed China and they are not the center of the universe so no need to worry too much about their decision, they used to make bitcoin wobble when they issued a ban but bitcoin overcame it all and got stronger and stronger. I see bitcoin now no longer influenced by Chinese news.