I'd be interested in hearing what you have to say from the technical side, in case it contains any information that is new to me. Personally, I model things such that if a closed software/system has access to some information, it will backhaul, store, and abuse that information (if not immediately, then in the future). I'm not going to hang my hat on a hope that some companies aren't functioning as optimal surveillance machines!
FWIW I don't find privacy policies themselves particularly enlightening because they're generally vague, equivocating, and subject to change at whim. Sure technically if there weren't a "privacy policy" then you might theoretically have some legal right of action to go after a company for abusing your information (although good luck demonstrating real damages, as always). But at least in the US that feels completely hypothetical.