I have a 3kW electric kettle, and a 2kW induction hob, and I find the induction hob faster and more convenient. (My wall sockets are all 240V.)
However, I’ve just actually measured it, and the situation is more complex… I timed how long it took each of them to boil a single cupful of water. Unsurprisingly the 3kW electric kettle boils the water much more quickly, but it takes ages for its temperature sensor to notice. The electric kettle turned off at almost exactly the same time as the stove-top kettle started to whistle.
So for small volumes of water, it’s a draw. For larger volumes of water, the electric kettle is noticeably quicker.
Why then, do I find the stove-top kettle much more convenient? I think it’s because it has a better “user interface”. When the electric kettle has boiled, it clicks off and I often finish whatever else I’m doing before going to use the hot water. By then, it’s usually cooled down a bit, and I have to turn it back on and wait to bring the water back to the boil. (Actual boiling water is very important for making tea.) OTOH, the stove-top kettle whistles and stays boiling, so I am forced to go and deal with it immediately. The result is that I get my tea made a little bit quicker, with less waiting around.
Interesting. Perhaps electric kettles should replicate that UI, by having a continuous alarm, instead of automatically turning off.