I grew up in Texas without an electric kettle. If we needed small amounts of hot water, we used the microwave. Otherwise, we boiled it on the stove.
Then I spent a semester abroad in Ireland, where the house I lived in came equipped with an electric kettle, and where I drank more tea than I ever had before or since. It was absolutely essential to all of my Irish housemates, and by the time I left, I agreed with them. So when I got back home, I went out and bought the only electric kettle sold at Bed, Bath, and Beyond. It cost me $50, but I still have it and use it daily 8 years later.
I also convinced my mom to get one a few years later, and she liked it so much that she gave one to my brother and sister-in-law. They liked it so much that my brother's parents-in-law ended up buying one as well. I don't think my sister owns one, but I'm pretty sure she wants one. So my whole family can thank the Irish and my time abroad for this wonderfully convenient device.
I now live in the Pacific NW. I don't think anyone else I know has an electric kettle, but I do see quite a few models for sale at places like Bed, Bath, and Beyond, and even more for sale online. When I bought mine, it was just about the only one available (else I'd have looked for one a bit cheaper than the $50 I paid for it).
I have become much more of a coffee drinker than a tea drinker, but I do use my kettle when I make tea. At the moment, I primarily use mine for pre-heating my coffee thermos and making instant oatmeal, but I love the fact that I can flick the button and go do something else while the water boils. I also love the auto-off feature, because I frequently am involved doing something by the time it's done boiling, so I can ignore it. I do sometimes have to re-boil the water, but it goes faster when it's already hot, and I figure it's just extra sanitized.
Unless I'm actually cooking on the stove, I never use anything but my electric kettle to heat water. It holds 1.7 liters, and even when I need more than that, it's often still faster to just fill it up twice. It's way faster than my electric stove, and way easier than the microwave. I live in an area with very soft water, so I can't remember the last time I had to clean the inside of the electric kettle. I actually don't know that I've ever had to clean it. Even in my apartment kitchen with limited counter space and outlets, my kettle has a spot on the counter and a dedicated outlet. It is, in that respect, as essential as my toaster, my microwave, and my coffee maker.