It's still early days for this tech. Right now its maximum output is 800W, which is not a lot. OP mentions this delivering 3kWh on a typical day, about 10% of a typical US household's consumption.
But it's the direction of travel that is interesting here. This will get better, and cheaper. Then systems like it will be able to deliver 25% of daily consumption, then half. All with affordable systems you can install and set up yourself.
Many people have nightmares about dystopian and apocalyptic futures. I would feel safer in a world where electricity production was decentralized and could survive major disasters.