Hi Hedgehog - thats a great point. We thought of it, and when you're not doing a gesture, CPU usage should drop to around 2-3%. Let us know if it doesn't. In our test, average CPU usage was around 5%.
Interesting. It does seem to drop to about 5% if I'm not in front using the computer and not in front of it but otherwise floats between about 7% and 20%. This is on a MacBookAir4,2, based on a few minutes of testing it seems like it's about 65% additional power consumption when the machine is otherwise mostly idle. I'm actually impressed though that you got power consumption as low as it is. Photo Booth consumes about 6.5% so I'd guess that's the lower limit for Flutter, maybe default to disabling Flutter while the computer is on battery?