Ask HN: practical uses for gesture detection?

I've been working on a technology that I can't find extremely compelling uses for. Here's what it is: you wear a device on your wrist, and can wave it around in various configurations (gestures) which are detected. Then you do something...

Aside from vague consumer-type applications that you'll see in mock-up videos (e.g. https://www.thalmic.com/en/myo/), what are some real value-add uses of this technology? Even if it's for a very small amount of people - in fact I'd prefer that so I can design a custom solution.

Thanks for any ideas / advice.