For photosynthesis to proceed on a planet like Earth, sunlight (visual light) must penetrate the atmosphere all the way to the ground.
One or two examples are interesting. But where the argument gains dramatic force is in the accumulation of many examples.
Like you, I was blissfully unaware that our atmosphere was being bombarded, and only stumbled upon the fact a few days ago.
Extremely improbable events must be macroscopically (simply) describable to be forbidden.
Yes, rainbows are beautiful, but are they good for anything? Indeed, they have been very important for science.