Most apps are free, but they drain from you precious data.
Is that free? No.
This data allow them to know you and predict your behavior, consumer and voter trends. And once you're partly transparent to them it's easy to be manipulated. Hundreds of thousands voters got targeted and influenced in the Brexit and Trump votes during the Cambridge-Analytica Facebook scandal. Google is even more powerful.

The most sensitive App Permissions are :

  • Body Sensors : that data tell how much you move, and insurance companies are ready to pay much money to do their due-diligence before accepting covering you.
  • Microphone : apps running on background are actively listening to recognize keywords, like "Ok Google" or other commands. Of course knowing what we talk about is also precious to profile us further. The component "Alphonso Automated" is an in-famous one.
  • Camera : If you haven't covered your selfie camera with a sticker, then it can easily eye-track where on the screen you're looking and how you react to each visual content. That's an powerful psychological assessment method to finely profile your reactions.
  • Location : Knowing where you go, when, how fast, and roughly who you meet (cross checked with conversation content if you allow the microphone), that too is very sensitive.

Click on the image to enlarge