Researchers from IMDEA Networks, in collaboration with Universidad Carlos III de Madrid, IMDEA Software Institute, and the University of Calgary, have conducted the first large-scale study—“Your Signal, Their Data: An Empirical Privacy Analysis of Wireless-scanning SDKs in Android”—on how certain Android mobile applications use a device’s WiFi and Bluetooth connections to track users’ movements in their daily lives, thereby violating their privacy.
This is why both should be turned off when not explicitly in use.
I’d say it would be better if there was more transparency into the APIs and sdks being used by which apps.
That, or a Linux os.
This is why I run all non FOSS apps on a work profile via shelter and keep them frozen until I need to use it.