Eldrazi runs Chalice of the Void which can lock out your one-and-two-mana spells, so Barrowgoyf gives you a meaningful body to block Reality Smasher and Eldrazi Linebreaker while growing with graveyard card types. Consign to Memory is excellent since their whole deck is colorless spells like Thought-Knot Seer, Eldrazi Linebreaker, and Kozilek's Command. Thoughtseize comes out since many of their key threats and Chalice are hard to interact with via discard once committed, and Daze/Street Wraith are low-impact against a deck that doesn't care about tempo the same way blue decks do.