I can't speak about this specific project but pose tracking in the browser can actually be really useful to get it on mobile without the need for dedicated apps.

We are currently experimenting with using phones (or tablets or basically anything with a browser and a camera) as a tracking source for full body tracking on the Oculus Quest ([1]) and being able to just use a Tensorflow model in the browser has cut down the time of development on the mobile device side to almost nothing.

There are of course a whole lot of other issues one buys into with that approach (browser security policies, the whole thing not working in certain countries due to problems with loading the model) but that's manageable

[1] https://www.youtube.com/watch?v=zz9S5hgrWpM (relevant part starts at 0:29)

I found this demo of him playing "Into the Breach" with only Face Gestures very impressive! https://twitter.com/GoingHandsfree/status/140022171083874713...

I made a slouching detector a while back. It calibrated the distance of your face from your laptop and if you start leaning in it’ll give you a notification to sit back. It’s a bit dated but still works on Chrome and FF, I believe:

https://slouchcam.com

You could integrate this with adtech to help make advertisements more interactive and to analyze how the viewer is receiving the ad by their pose and facial expressions. Based on that you could have an algorithm serve only ads that improve facial expressions and poses to positive ones

WebXR comes to mind.