The point was the other parts of the plane. No lines moving all that gas around and the pumps and the plumbing in and around the engine and the bleed air piping and the and the and the.... There are a lot of potential places to shave weight when you go electric. An aircraft optimized for electric will be massively different if done right.
The way jetliners scale shaving the weight of those things (and note that you're not counting the weight of electric cables that can carry hundreds of amps) is nothing. It might be something for tiny airplanes, but that's it.