You can even use it to fuel self-mill and not sacrifice it if you absolutely had to
They either have no use for Ulalek, Fused Atrocity or can be replaced very easily with something better
A Fair combat deck might be swinging in for the win once it amasses a board
However, as people played the card more and more, they realized that casting a small Sphinxs Revelation for two or three would gain them the life and give them the cards they needed to prolong the game a little later, in which case they would want another Sphinxs Revelation for five or six
Korvold is infamous as being one of the strongest Commanders in the format
While most doubler effects are super easy, this one requires you to fill your yard before you get any benefit, so to me that takes the card from busted and boring to wow, actually interesting