I wonder why Omens of the Third Age has no super rares

[komfyrion]

I thought Superslam was the reintroduction of super rares to the game, but the rarity has been absent of late. Perhaps it made limited too swingy based on dumb luck in opening them? Or maybe super rares just don't work so well in a world with Silver Age, where you'd prefer to give some would-be super rares to Silver Age, so they are rares instead.