The sand storage is used for district heating. It's not much of a substitute for single homes that have electrical heating or are off-grid.
It's a great way to balance both the electrical and the heating grids so that more electricity from renewables can be used to offset other means of heat production, but it needs to be done by the district heating supplier. I doubt it makes sense for individual houses.
Suburbs are fine for district heating, but it's a massive long term investment.
For UK in particular, I also think proper insulation and triple/quadruple window panes are much needed to curb with the increasingly scorching summers and freezing winters. I was surprised to see soo many houses with single paned windows in London.