I can offer ‘olde basterd’ reasoning for 120/240V service to electric cook tops and clothes dryers. On cook tops, burner heat levels were varied by a switch connecting two different-wattage heater elements per burner to a combination of 120 or 240V.
Clothes dryers used to have labels on their backs showing operation on 120/240V OR 120V only. At 120V, the 240V 4500W heater would work at only ~1100W, but it was intended to as needed.
