Thinking more in terms of emergencies. Helpful to have someone there in those cases.

For longer trains you could make that case, though it should be the agency that makes that call, not politicians that don't have the information to make technical safety calls. Systems across the world don't seem to have issues here though. In any case, there's no world where one employee is enough for emergencies in two cars, but not enough in three, while two employees are sufficient in a train with ten cars.