It's not just what you post that you give them access to. It's everything on your devices.

A possible use case? When are people more likely to be in certain areas? Essentially create population heat maps for use in a tactical war with the US for mass casualties. Or, perhaps, ways to politically influence the US for the benefit of China (like Russia has done).

Information is very powerful, and China is getting free access to droves of it.

Space actually needs a lot of coatings. Microdebris, radiation, and EMI all need consideration. Oh, and Thermal. But yes, a specialized spin off would be interesting!