It's an interesting idea, but at the same time not one where there is a lot of video game application. Gas pedal I suppose, but given the relatively little amount of travel, I wonder how much control such a button would yield. Probably better to just rig up an actual pedal. It's easy enough to make a separate piece that could be connected/disconnected.
Where I could see this being used is for music controllers. It could be put into something like a MIDI Fighter controller, but with analog switches for different velocity (volume) levels.