The lack of trust in the purchase comes from Apple, not from this seller. It's apple that's reaching into your device and force updating the firmware without your consent.
> if it stops working.
It doesn't magically stop working though, it would be apple explicitly putting in effort to break this functionality and forcing you to update a device you own, forcing you to use it only how they want you to use it.
Or is that why the tag flashes and makes sounds frequently so that people without phones can know they’re being tracked?