I think it only works within a narrow vertical plane. Meaning, you couldn’t have it mounted to the mirror frame directly, and interact with the mirror 6-12" away. See the example in the video where the kid is hitting the wall from a projector, with the sensor mounted to the wall itself.

I think you’d need some sort of extension, kind of like what’s used in picture lights, to put the sensor far out enough so you could use it like an air mouse rather than a virtual touchscreen.

Unless you do want to touch your mirror.