A man who has fallen from a higher station is not cast out but given a lower charge, and the lower charge still matters. These Levites lost the nearest place and were set to keep the gates and kill the offerings, the bloody, unglamorous labor at the threshold. Demotion is not annihilation. A person answerable for a smaller and humbler duty still stands inside the order, still serves the house, still holds something together that would collapse without him.
Guarding the gate matters. Someone must decide what passes into the sanctuary and what does not, and someone must do the hard, hands-on service the people cannot do for themselves. To minister is to bear a burden on behalf of others without acclaim. The station is reduced, yet the dignity of the task remains. A man serves where he is placed, and the serving is what makes him worth something.