I dunno. TBH I'd rather just let the food go bad than bother with the expense and hassle of having a battery and keeping it charged. I guess other locations may have less reliable grids than I do, but I've only experienced one power outage that lasted so long[1] that our food went off in my entire 40 years living in the Twin Cities area.
[1] About 96 hours, major storm took down a ton of trees through the whole metro area that took days to clear.
The device's primary use would be using excess solar power from during the day, or excess wind on rare occasions. This would just be a nice benefit and I just meant that it doesn't have to keep up with the whole house during an outage to still help out in a pinch
I can't even remember the last power outage we had that was not self-inflicted (a year ago our old microwave oven permanently tripped the residual current device).
Also, according to the article, it seems to pay itself back in 11-12 years. I'd rather pay the little extra to not have a huge lithium battery in our appartment that cannot be extinguished with a normal fire extinguisher if it decides to ignite itself.