In a heating appliance, the actual surface temperature of the heating element is probably 1200deg F, so at 208V would be 800F, still a LOT more than the air temperature you cook with. So other than the time it takes to change the air temperature in the oven, it’s not that relevant. Ultimately, the only consistent effect is it’s recovery time after opening a door, or convection losses through the walls. Most people don’t notice.