I've heard of people using it in L7 (piked though, not straddled, but I've never seen it around here), so I guess they do. Or maybe you would just get the high to low transition...but then that wouldn't really account for why it's being used in L7. It seems unnecessarily hard to kip out of, and like you'd need the bars closer than most JO teams usually put them, but I've never tried it, so who knows.