You going to worry about alot more than powering a 20W light bulb if that happens...
Having a lot of small appliances/ low power computers ecetera can be powered with those things especially coupled with a battery storage system. I know of a missionary group that put together a village water pump system which also produces enough power to light and power a small mission health clinic in Burkina Faso using a bank of 12 storage batteries and a couple of your average solar panels...(I don’t remember the square footage just the picture of them which I estimate to be less than 200 square feet of panel.)
One of the other posters on this thread says(post 11 JRandom) he lives to far out for utilities so he needs solar power though he admits his power needs are small.
What my point is, is that having access to a power system like this might make a difference between survival or death...it stands to reason that one might not power a whole house hold full of energy sucking equipment but one might power a radio or small tools or medical devices. And yes being able to power a few light bulbs as opposed to living in the dark with out access to replacement candles makes it so that life doesn’t have to totally suck!