China wants to ban anything that remotely threatens its centralized authority. It's not really a surprise to see where and why they do all the above you said. They would lose nothing as the benefits of total authority government style stood higher than anything else. if more people knew that, they might start come to the acceptance point and not give a shit about China. All for the better, less time to waste on things has no end, I would say.
Basically, China wants to stand alone with its own products, without the need to use other countries' products. It's not just Bitcoin Cs that is banned by China. Previously Google was not even allowed in China, all Google products were blocked from China and Facebook was blocked starting in 2009.
Now Bitcoin is on China's block list. maybe China will make its own bitcoin, and create its own network, because of the nature of bitcoin that cannot be regulated by anyone or decentralized, then China rejects Bitcoin. But I am amazed by China, being ability to build its own country with endless innovations.