Comment 5 for bug 1000981

The rate-dir preference exists so that skins and controllers attach one button to rate_temp_up and one button to rate_temp_down and then the preference options toggles the direction without having to change the skin mapping or controller binding.

If rate_temp_up always meant "increase the speed" then the burden of implementing the preference option would be on the skin and preset authors since they would have to rebind their mapping to rate_temp_down when the preference option changed. It's better that it's transparent and rate_temp_up means the up/right-facing button and rate_temp_down means the down/left facing button.