No mention of the irony of someone who doesn't use Google Play Services because he only uses open source software being willing to attach a device to his car, running closed source software, that tracks everything he does in his car?
We need these "personal data for discount" transactions to become more explicitly consensual. Despite the well-tuned sensitivities of those in this community, we have a long way to go before most consumers are informed about this unwitting marketplace.
Depends. A lot of doctor's offices are in "medical parks," so it's entirely possible they don't know which doctor you are seeing or why. They have easier access to that information via your calendar (if you use it) than your location.
For that matter, your location data couldn't be proven to be yours on merit alone. Anyone can be using my car, and anyone can have my phone, at any given time.
I suppose it's good in case your account gets leaked.