I think the RN view is that until you are actually firmly on the deck it is better to not be attached to the ship at all!!
Surely an issue with the haul down is getting the aircraft to connect to the ship whilst hovering (how is that done?), I guess that needs a team on the deck, the RN view is probably that (certainly for Merlin) the deck is unmanned, which given the sea states required to operate in, is safer than having people on a wet moving deck.
Both Merlin and Lynx/Wildcat have significant subminimum pitch available to stick the aircraft on the deck until the harpoon engages (which takes a few seconds at most) only when secured by that are the engines shutdown and either the aircraft moved into the hangar or lashed down.