Guthooks seem to sell to the newbs in hunting. Most experience field dressers resort to a small droppoint, 4 1/4" max. The droppoint does exactly the same job, slips under the skin edge up and slides along the top layer of muscle, cutting the hide from inside out.
Actually using them to hook guts is precisely what to avoid - which is pretty hard to do, considering the layers above them.
I've seen and heard folks using the hook to grab pots by the bail handle off the fire, but steel on steel is a great way to dull it.