Deanwvu

Hello all, Forgive my ignorance, that's why I am here--to ask a question. For the player, we have to expend soul gems to recharge our enchanted weapons. However, it appears that if I give a follower (Lydia, in this case), she can use said enchanted weapon indefinitely, with no need to recharge it. Is this true? If so, its a bit crazy. I gave her the Staff of Magnus, and she is tearing things APART with it. Almost makes it too easy! Thanks!