…wait, they already did! The Fire has that.
Maybe it's so that they can detect whether or not people are at home - To aid with their drone delivery system?
Before I read TFA, it was the only business reason that made sense to buy a car charger company. It wouldn’t be perfect information (maybe I took the motorcycle that day), but long term you’d get a pretty good idea of our comings and goings. When the car’s at the house, it’s usually plugged in, the charger knows it’s plugged in, and the charger has an internet connection (hell, the charger has a web server running). Unplugged: I’m leaving. Plugged in: I obvious just got home. I suppose that might have some utility for scheduling deliveries, dunno.
The reason for this tangent is the purchase is either to aid in delivery scheduling, of which I’m skeptical, or it’s just another piece of the puzzle to go along Alexa and the like. Now, I’ll agree that the puzzle might end up being super creepy, but it’ll be interesting to see what they up,doing with it.