I got one as a gift. So dumb. Just what a I need in mug: IoT and a charger! /s Plus, I can just microwave a normal mug to heat it back up, but not this. And forget about the dishwasher.
...except now that I've used it. It's pretty fucking nice not having to go over to the microwave when I inevitably forget about my drink. And if I use the charger as a coaster. That battery is always topped up. So, I understand its appeal.
Tl;dr: It's dumb, but it's also actually quite nice. I certainly wouldn't buy myself one, but I enjoy using mine.
Just don't connect smart TVs to the internet. Get something cheap like a raspberry pi + wireless mouse/keyboard or an android TV box for the same functionality. (More functionality, actually)