That just had me think for a moment, what about offshore yuan limitations? If China bans all other exchanges, then they're effectively limiting capital flight, aren't they? Because I thought each citizen has a limit for how much yuan they can exchange per year to prevent it all going out of the country into foreign property, gold, dollar, bitcoin, etc.
Technically there is an annual $50,000 limit to what people are able to move out of the country, but in reality due to various restrictions and how banks are instructed to work against foreign capital transfers, it's likely well under $10,000. People however don't necessarily need to transfer capital to foreign countries in order to buy into Bitcoin. It's pretty similar to how drugs get smuggled in the country. There are so called Bitcoin mules (mostly from neighbour countries) entering with Bitcoin and shortly after leave with cash.
So if they're permitting a select few to operate, it means that they are letting their citizens use bitcoin, under certain circumstances. They'll probably collect additional tax on it or something.
I don't think they collect tax since it's legally prohibited to use crypto in combination with fiat, but it would be great if someone from China could add some valuable input when it comes to why these exchanges are allowed to operate.