I don’t drink much tea at home but I still use it all the time for pasta, eggs, instant noodles etc. literally any cooking that needs boiled water.

I have a kettle and it has never occurred to me to use it for cooking food.

Just to be clear, don’t put food in the kettle! It’s just a lot faster to get water boiling than starting from cold on the stove.

Especially if you have an induction stove, where the stove itself is hot instantly so you can pretty much just pour the water from the kettle into the pot and start cooking (unlike a resistive stove, where the water often cools quite a bit before the stove catches up so you end up waiting a couple of minutes after boiling the water in the kettle for it to be boiling on the stove again - still faster than going from room temp on the stove though).

Very much not the case for me, with a (fairly good) US electric kettle and a natural gas range. They're comparable, speed-wise, for smaller quantities, and if I need to boil more than a liter or so, the stovetop is a lot faster.

Elsewhere in the thread voltage difference are brought up—that's probably what does it, typical US wall service is far lower-voltage than in Europe. That, and I've definitely had electric ranges in the US that were incredibly slow to boil water, so that might be a factor. Gas, though? At least as fast, depending on the quantity. (I hear induction electric is even faster, but have only used those a very little bit at a couple AirBnBs, so don't really know, first-hand)

For me, in Europe, my electric kettle boils water maybe somewhere around 3-5 times faster than my gas stovetop. I usually use it to pre-boil the water when cooking as that saves so much time.