An excellent point. Which is why I don't share my Fitbit data (uninstalled the app after set up, no syncing of data) with Fitbit (now Google) and will (assuming it works as advertised) likely be moving to a MiBand with GadgetBridge[0] in the near future. And thanks to vanous[1] for posting[2] here about it a couple weeks ago.
I have no interest in sharing my health (exercise regimes, sleep cycles, heart rate, etc.) information with folks whose raison d'etre is to snarf up as much data as possible. What's more, since these folks aren't "covered entities" under HIPAA, they aren't required to put in the special safeguards for your health data.
And more's the pity.
[0] https://codeberg.org/Freeyourgadget/Gadgetbridge
[1] https://news.ycombinator.com/user?id=vanous
[2] https://news.ycombinator.com/item?id=32965166
Edit: Fixed typo.