I must be a really terrible person. I have resisted the urge to fit such a thing for many years but now I do have one fitted to the left chainstay of my steel tourer. It doesn't get in the way of the left pedal, I can wheel it backwards without the left pedal colliding with it, and it makes it so easy to park the bike in my garage. It makes fumbling about with my panniers so much easier if I go shopping on the bike. It folds back out of the way like a penguin's leg. Would I fit it to a super light road bike? Probably not. It's aluminium, and the extra weight probably does not make much difference compared to the kitchen sink etc in my saddlebag, but it would just look so wrong on a road bike, despite being equally as useful. Just my opinion of course, you can fit whatever you want to your own bike.