Bruh, are you so focused on writing irrelevant walls of text that you're not even reading the stuff you're replying to? My specific issue is that the author does that. I said that's nonsense.
And the whole "amazed at reflection at night" business is pure stupidity. As the other guy so helpfully pointed out, you could have mirrors and artificial light sources in the fucking stone age. They have more than enough in that world for viewing reflections at night to be absolutely nothing special, but the author spins it that way anyway, like the isekaijins are morons.