This analogously is true for Improvised Weaponry if I am on the play and my opponent does not have a creature in turn two, I am most likely holding on to the Weaponry, which consequentially prevents me from playing my Ogre or Owlbear on turn four
This makes milling far more aggressive and also makes simply milling a potential answer to floodgate cards
For example, play it early, and sacrifice it to bring out your commander two turns earlier and with haste
Satoru, the Infiltrator Outlaws dont include ninjas, but Satoru, the Infiltrators ability still works as a ninjutsu payoff
FromTheShire: Also requires a somewhat specific deck, you want to consistently have a plan to be spending this much mana at instant speed anyway or else you're just sitting with all of this mana up not progressing your board in case a wrath happens
Making all of your creatures replace themselves buries your opponents in card advantage and makes it hard for them to interact with your board