We have one and I think it's incredible and incredibly useful. I'm curious about the "bad for the environment" comment.

Ours is a 2005 model and it is in pristine condition, has no scaling, because we descale it once or twice a year, and it still works as well as it did when it was first purchased. My wife is Chinese-American and "water pots" are standard fare in most Asian households. Ditto for Zojirushi Rice Cookers. For the record, our rice cooker is 13 years old, is used 4-5+ times a week, and both looks and works as if it were brand new.

How is this an improvement over an electric kettle?

The water is always hot. Instant coffee and beverages are popular there, so it makes a difference that hot water is ready to go with no waiting time. And in Japan at least, the household voltage is only 100V, so kettles take forever to heat up.

It wastes power (and AC load) but might save a tiny amount of time compared to a low power electric kettle.

They keep the water warm indefinitely, apparently.