User blog comment:Mcb172/Improved Flags?/@comment-34318882-20180222041611/@comment-34318882-20180223040146

Well, the stat plus and effect indestructability were because Darkness Dragon World has many grade one or less cards, which can be even better with those effects. Nearly every DDW deck (Deep, Death, Black dragons, Etc.) Have very strong Size 1's or less that are weak to destruction. It's a pretty good generic effect for the entire world.