On one hand, the potential privacy invasions enabled by this technology (e.g. Xfinity (of course Comcast) a few months ago[1]) are pretty scary.

On the other hand, the technology seems potentially extremely useful. I've had an interest in pose estimation for many years, but doing it with normal cameras seems tricky to do reliably because of the possibility for visual occlusion (both from the body itself and from other objects). I'm curious to see if I can use this for something like tracking my posture while I use my computer so I can avoid back pain later in life.

[1] https://news.ycombinator.com/item?id=44426726

Posture (how you position your body) isn't the cause or prevention of back pain.

Your muscles need strengthening, strengthening comes from movement, movement comes from mobility.

But you are right in that it is an interesting hammer to find nails for

If you want good posture and prevent back problems and pain, just do resistance-based training (get a good coach and/or physical therapist to get started). There are a lot of excercises for strengthening the back and the neck in particular. It is never too late to start.