I guess the first question is what is the reason for hair rigs? Do they increase hookup ratios?, keep the fish from swallowing the hook?
Not sure. Secondly, it would seem to me that the hook just swinging around bare would snag on everything.
They are for carp fishing... they are supposed to let the carp take in the bait without feeling the hook. So they are to increase hook-up percentage in a way.
The don't snaget any more easily than aelse.a regular hook.