My sister overcools her house so she doesn’t have to run the AC at night (but she lives somewhere hot enough for that to matter - I can just open windows most nights).

I charge my electric car on it (which I guess is stacking a bunch of batteries). I’ll also cook during that time to use the energy on that.

Around me the main current use case of these rooms is for landlords who have broken up a bigger detached house into multiple units to separate these units with 2-3 doors leading off into different units.

Honestly I found that endearing.