Protecting electronics from electrical surges - plugs with fuses
The UK uses fused plugs because instead of using individual spurs or "home runs" rated at the receptacle rating to feed a few outlets at a time, they put all receptacles on a single "ring main" circuit that can provide more current (32A is typical) than appliances and their cords can handle (16A max, although smaller is common with BS1363 plugs).  It has nothing to do with surges or grid instability.