[chopin]

The app will likely have access to a bunch of unique identifiers on the phone. At least on Android whichs core concept is spying on the user.

For me, it's enough that your activity could be linked to any unique identity. I don't want mandatory government apps on my phone, that's very chinese. We should strive for better.

Edited to add: your linked FAQ conveniently leaves open how the communication between the web site and the app happens. There are myriad of ways that ones behaviour leaks in this step.