YMMV, but I'd dropped my iPhone covered only in a ZAGG and had no problems. Sure if you drop it hard enough to damage it, yeah the skin won't protect it. A hood skirt would protect against road grit, which is what it's intended to do.
All I can say, I think ZAGG (while a bit more expensive than I'd prefer) do a nice job of what they're supposed to do and do it well and look nice. You're welcome to your opinion of course