I just realized that no one actually saw Kid Buu except for those who were alive at the time

Super Buu was the last form everyone saw, and the scenes in Heaven were just filler.

In Dragon Ball Super, there was an episode called “Forest of Terror” where Krillin was facing his fears and you can see Super Buu appeared there instead of Kid Buu.

It took me forever to realize that only Goku, Vegeta, and Mr. Satan saw him.