I have sometimes wondered about these, given I am an ex M3 owner. The question I have is that given they must be raised to rotate / wind is there any risk that over enthusiastic winding might cause a collision with the camera top in proximity with the winder thereby damaging the camera top plate. Of course when only the finger and thumb is used instead, this is not really an issue. Overall though it seems like a good idea that has stood the test of time - how long have they been around - what perhaps 15 years?
EDIT: Oops I see someone has beaten me to the punch with this question.