Wouldn't something like this be potentially quite useful if you live in an area that could easily see a natural disaster that results in weeks without a connection to the outside world? Sure you could build a raspberry pi to do it yourself but not everyone is capable of doing that and its also a low power consumption device which is useful to keep your backup power going longer, ideally through a battery as a generator normally doesn't do very low wattage efficiently. Solar is variable and lower power demands means you can go smaller, or helps keep it more reliable.
I find prepper stuff has a fine line between reasonable preparation for something that may well happen and then you get into the crazies that think the world is ending and they are actually going to achieve anything in such a situation beyond dying alone.
As I live in the UK the most likely disaster is a couple cm of snow which will break most infrastructure, shops will run out of things like milk and bread for days. This happened a few years ago, I had to resort to making tortillas instead for my lunch.