Question asked was does anyone use one. You've heard from those who do. I don't. I'm generally technology averse in hunting, but really see no need for one. I don't have difficulty judging range to 20-30 yards, and if I'm in doubt, it's a simple matter to pace it off, particularly if setting ground blinds, or even walking a distance from a tree stand.
I suppose they might work better for those who use a mechanical/fixed aiming system, where knowing the exact range can assist in where to hold the arrow point, but i shoot more instinctive/split vision. Can be useful as a training aid in shooting longer distances, as Rob suggests, but knowing the precise distance to the critter under hunting conditions is of no value to me.