I think if you did a lot of typing the noise of all those bits inside rattling might annoy you [David Ross - this would absolutely kipper you, you rattly old typist. Bob]. And it wouldn't work for me because I turn my keyboard on its side when I'm not using it to give me more desk space and I guess everything would fall out. Plus I need a curvy keyboard.
Otherwise I can't see it doing any harm as long as the keyboard is good quality and it's certainly more useful than the Jegs Finger Disco Light.