Problem is: 1. Precise location of tracked object, now
This is actually one problem and Apple didn't solve it very well, airtag doesn't work in real-time. You only get updates when there are people near object that uses iphone.
An AirTag might help me find my keys if they fall out of my pocket in a restaurant restroom. A cellular-based tracker won't because (1) it will be out of battery, and (2) it won't have a GPS signal.
Ok? In practice, this is most of the time. In most reasonable use cases (i.e. excluding the Sahara desert or some remote mountain).