That's kind of a special case, one couldn't pick a situation more tuned to the strengths of electric. The big burner on the stove heats the air up a ton, including a huge amount of heat going around the pot, straight up around the edges. (Add more inefficiency if the pot is uncovered). Whereas the electric element in the kettle is inside there conducting almost all its heat into the water and the insulated kettle is great at keeping the heat in (my kettle doesn't really get all that hot on the outside).

Stir-frying in a wok, for instance, will not be nearly as lopsided a win, but it will still be more efficient.