I would hope the whole thing is a joke in general.

"The sun gives us light when it's 'already' bright" is where the real logic breaks down. "I don't need because I already have " is circular logic.

So of course we wouldn't have sunlight at night without the sun. but we also wouldn't have sunlight at night without the moon.

Whether we want to call it "more useful" than the sun... it is just as useful as the sun at night. We need both of them for the system to work. I was just trying to snarkily emphasize that we shouldn't downplay the moon because it is "just" reflecting sunlight.