Just try a hovering autorotation from 10' AGL with a slight delay from simulating the failure till raising the collective (and only raising the collective) to cure you from ever, ever, ever hovering above that height for more than the briefest time.
It's one thing to hover at more than 10' AGL with full knowledge of the consequences and with good reason for being there, and completely another thing to do with and not know what can happen.
The reason for the only raising the collective, as opposed to the standard training technique of smartly down with the collective followed by an almighty pull, is that nearly everyone who's ever had an engine failure in the hover has said that it all happened so quickly that all they had time to do was pull up on the collective. Good reason why the HV low hover test point is required to be demonstrated that way.