I think it's safe to assume that the code used to recognize cars and traffic signs can also be used to recognize other things, such as muslims, people using app

I think it's safe to assume that the code used to recognize cars and traffic signs can also be used to recognize other things, such as muslims, people using apps the government can't spy on, people wearing/holding objects that the government want to eradicate (perhaps a banned book). I think it's also safe to assume Google benefit immensely from having millions of people ready to test their changes in order to optimize their code and algorithms. I'm also sure that they do more than just check if you picked the "right" squares, such as storing every square you've ever chosen along with other stats such as completion time and correctness. I wouldn't be surprised if the Chinese government (as well as others) had interest in using such data to detect "rebels". I would also be surprised if the work wouldn't be beneficial to other AI related work that can be used to build detailed profiles among other things.