That's annoying, but it only seems to cover tap detection by accelerometer where I was thinking of tap detection by audio click, which definitely seems plausible from a quick test of the sound recorder.
Also it only covers finger swipe detection/direction determining, where I was also imagining gestures from holding fingers a few centimeters away, such as scissoring two fingers, thumb/finger flick, two finger scroll movement, two fingertips touching, etc. A quick test with the iPhone camera suggests that might have to be too carefully positioned to be practical, but should be possible at some level.
Also it only covers finger swipe detection/direction determining, where I was also imagining gestures from holding fingers a few centimeters away, such as scissoring two fingers, thumb/finger flick, two finger scroll movement, two fingertips touching, etc. A quick test with the iPhone camera suggests that might have to be too carefully positioned to be practical, but should be possible at some level.