I wrote about it in another thread, but the planet Uranus was almost named Herschel.
It’s funny that DC Comics really liked to give special significance to the colors of things. The different Lantern Corps groups, the color of suns, the color of Kryptonite. Rainbow Brite would have fit in pretty well there. Heck, Superman has had rainbow powers before.
They really should do a sponsorship with Skittles at some point.
I imagine it has to do with the colorful medium of comic books, and DC in particular liked their very bright, colorful aesthetics.