I also don't understand cycling-specific leg warmers. My kneecaps and shins can handle most any amount of cold-- if it gets cold enough that my shins are cold, the whole wardrobe needs to change. So yeah, now you put on leg warmers, and you've got toasty kneecaps. Meanwhile, your junk has frozen solid, because normal shorts/bibs don't insulate at all.

Further, that pic with the Castelli warmers is showing an almost scandalous amount of ankle.