> While the time savings is modest, if you have an electric kettle it's a no brainer to prefer that over gas.

Not quite. Water is heavy and boiling water is dangerous; if you're boiling your water in a teakettle you then have to transfer it to a pot on the stove without scalding yourself.

(This isn't the exact problem I'd experience if I adopted your advice. I have an electric teakettle, but it is low volume and is also sharply limited in the rate at which you can pour out water from it. That's fine if you want to prepare individual servings of tea. It's unworkable if you want to prepare a bunch of boiling water to boil stuff in. But fixing that problem will immediately cause the "boiling water is dangerous" problem.)