AFAIK that's because granting access to bluetooth potentially allows the app to track your location (via bluetooth beacons). As a result both iOS and Android show the location warning just in case the app wants to do something malicious. Just because you see the warning doesn't mean the app is trying to ship your location to China.
On iPhone, bluetooth is presented to the user as a location check. Big data companies will if you're near your toothbrush then you're at home. And they can figure out where "home" is by other tracking methods.
>Big data companies will if you're near your toothbrush then you're at home. And they can figure out where "home" is by other tracking methods.
You don't need bluetooth to do that. By keeping track of your public/private ip (which requires no special permissions), and correlating it to time of day, it's fairly easy to infer whether you're home or not. If there's a network you're regularly connected to during the evening and weekends, it's highly probable that you're "home".
