If solar could reasonably double for me as a way of weathering a several day power outage in the winter, it would be more interesting. But I'm deeply suspicious of anything that has people out in front of Home Depot hard-selling something that often has complex financing schemes. I don't have huge power bills relative to lots of other home costs. So I'll pass.
DIY doesn't come with those asterisks, and DIY with only-thermal power use & energy storage is on the simple side of things. "Help me heat in the winter" is basically the simplest use-case, because you can accomplish it with a south-facing solar fence and some resistors [or an inverter + space heater, or whatever].
Personally I like the idea of a three-season thermal mass store, a big tank of water or pile of sand that you dump heat into when it's sunny, and extract it at will the rest of the day/week.
