Every slider implementation I've seen on the web has been inspired by sliders in iOS, where they provide a bigger touch target. iOS sliders also give considerable information about their current state: the word "OFF" is in grey text on white, and "ON" is in white text on a vivid blue background.
I agree that they're not really appropriate on desktop browsers, and I haven't really seen an implementation of them that impresses me or gets it completely "right."
I agree that they're not really appropriate on desktop browsers, and I haven't really seen an implementation of them that impresses me or gets it completely "right."