China sees mobile app stores as an untamed frontier with too much free expression and rampant malware, and it's determined to put a stop to both. As of January 16th, the Cyberspace Administration of China will require that all app stores register with the government, ostensibly in a bid to improve security. Some stores are terribly managed, officials argue, and offer apps that pose security risks, tread on your rights or contain "illegal information" (read: political dissent). Registration theoretically raises the baseline quality and makes sure that these portals obey the law.
You could see a demand like this coming. China passed a law in 2016 that prevented apps from doing things that allegedly threaten national security or the social status quo, and just recently had Apple pull the New York Times' app in a likely bid to enforce that law. A registration requirement ultimately helps enforce this measure -- the government will have records that it can wield when it wants to target apps or whole stores.
This could have a positive effect for Chinese smartphone owners, since they don't have official access to Google Play and its tighter security screening. Stores that frequently permit frauds and viruses could find themselves in hot water pretty quickly. However, it's bad news for anyone hoping to offer apps that normally won't make it past the censors. Locals might not have much choice but to sideload apps or otherwise work harder to get those titles the government doesn't want them to see.