Controlling a computer at maximum speed inevitably means occasional fumbled inputs. If I don't detect these, my mental state will desynchronize from the computer's state, resulting in confusion and potential data loss. Therefore I can't look away from the checkbox until I confirm it changed state. Any animation slows down this confirmation, so it wastes my time.
Professional StarCraft players take about 200ms per action, which is about the reaction time of the human visual system. If you set your time constant to that (1/e in 200ms, which would be an extremely sluggish UI) then your UI elements will have moved by 15% in 33ms. A more reasonable response (1/e in 50ms) will have moved by 50% in 33ms. My personal favorite curve is just "move 50% per frame."
I'd love to see what your day looks like if you've optimized it to require professional Counter Strike reflexes to activate toggles.
That 200ms is the natural human delay. A "reasonable" 50ms animation is in addition to that, so it's equivalent to making the user 25% slower. It's similar to moderate alcohol intoxication.
I personally use 72Hz keyboard autorepeat, which requires both low latency and predictable latency to use effectively.
