The behavior of the People’s Republic of China regarding bitcoin has purpose far beyond controlling bitcoin.  As background, The Wall Street Journal had this assessment of the PRC’s financial industry:

China has digitized its financial sector faster than any other nation.

The reason for their rapid pace is this according to Li Lihui, a spokesman for the National Internet Finance Association of China, and it has nothing at all to do with a sovereign nation’s legitimate desire to control its own currency and money supply:

A goal of China’s monetary regulation is to ensure that “the source and destination of every piece of money can be tracked[.]”

That end-to-end tracking, to the extent it can be done, guarantees that the PRC will know who is spending and for what.

And that means that the PRC, a nation that rules by “law” (rather than operates under rule of law) and that brooks no dissent from the pronouncements of the Communist Party of China, can control whether any given individual or organization will be permitted to spend for any particular purpose—or even whether that person or individual will be allowed access to his money at all.