MarkOz is correct on both counts, it does not do anything as there is no live galley model in the model.

In real life it enables the crew or F/E to isolate the galley (which has ovens and warmers etc operating) and therefore minimise the risk of fire and power loads during critical stages of flight. Galley could be on till take-off or beyond with no significant load, as no one does anything up back until cruise climb is established. If for some reason there is a malfunction or smoke or fire, galley power can be shut off from the flight deck. Happens from time to time. Galleys are wet areas and there is the ocasional short where wires get wet or rubbed. So hence the switch.

Aeroplanes I flew, galley power was off all the time until it was lunch or tea time, then on until food and drink was heated and served. Rest sat in big eskies, kept the stuff cooler if you kept the cabin temp right down which is controllable from the cabin like the galleys.