but it happens at a point where time is less critical. After a plane lands and the passengers depart, there is a race to clean, restock, and and board customer

but it happens at a point where time is less critical. After a plane lands and the passengers depart, there is a race to clean, restock, and and board customers for the next flight, so the plane can get back in the air. Any part of that process that can be made more efficient benefits airlines. Checking luggage likely reduces complexity during that narrow window, and adds it before and after the flight