Sex. Violence. Both those things sell, and they sell well. However, China isn't a big fan of "unwholesome" content, and they also have a problem with online gaming. In order to reduce the issue, they will be instituting a ban on sex, violence and gambling in the marketing of online videogames. This is part of a bigger push to limit the content and playing of online games throughout China. That push involves basically destroying the microtransaction market in the country as well.
Evidently, in China, hiring adult pornstars to advertise for games is a common practice. Here in the West we only do it every once in a while. I'm surprised it didn't catch on more after Saints Row 2's brilliant use of boobs. Clearly China is way ahead of the curve, it's too bad their genius is being crushed by an oppressive government. Damn commies.
What about all the pornstars who won't be able to pay their rent now? Did you think about them, China?