The main point of the deck is to create a lot of tokens (which are technically permanents) in order to trigger "Altar of the Brood". This will, hopefully, quickly mill out your opponents. If this strategy does not work or you somehow do not and have not had "Altar of the Brood" in your hand, then you could hopefully use the Eldrazi Scions / Spawns to cast larger spells or overwhelm your opponents. 

(p.s. I placed "Vile Redeemer" in the sideboard and only 2 in the Mainboard for a couple of reasons. First, the deck does not have any ways to produce colorless mana except for the "Sifter of Skulls" and the sideboarded "Birthing Hulk". Second, once the Scions / Spawns are on the battlefield you will usually use them for blockers or sacrifice them for mana. This will not trigger the "Vile Redeemer" as many times because non-token creatures need to die. Either way, you can add some wastes or simply sideboard all copies of this card if you want to play with this creature or not. I do not think that it affects the mill gameplay as much, but I won't completely know until I play more games with this deck).