[coryrc]

> No one is storing 1000C water at home.

Right, but UK has/had "storage heaters" which were bricks with nichrome wire. They would heat the bricks really hot during cheap electricity times, and use that heat the rest of the day.

EDIT: I misread "ripping out these energy storage devices" as https://en.wikipedia.org/wiki/Storage_heater

Of course heat pumps for DHW should all have a tank for smoothing demand across several hours.