But earphone cables rotate in place. So do the thicker kind of ordinary audio cable. USB cables don't rotate in place, but you have to exert a lot more effort

But earphone cables rotate in place. So do the thicker kind of ordinary audio cable. USB cables don't rotate in place, but you have to exert a lot more effort to twist them twice (so they plug in). Reversible cables have a lower barrier to twisting. (I'm repeating myself a little, but that's because what I had just written sounds confusing in re-reading.)