https://sunamp.com/en-gb/hot-water-solutions-thermino-range/
The phase change stuff has positives like taking up less physical space but it's also a much less mature tech than storing hot water.
In the UK there was a unfortunate trend of ripping out these energy storage devices and replacing hot water tanks with on demand electric hot water heating ( only heat the water you need ). And new builds often have no tanks ( as it saves space in the new tiny homes ).
Very short sighted in my view - a very simple way to store energy and everyone uses hot water directly.