This Eldrazi ramp deck is all green/colorless with virtually no blue spells, so Mystical Dispute comes in purely as a generic counter-unless-pay-3, hitting Emrakul, Devourer of Destiny, or Kozilek's Command for a tempo swing. Ashiok, Dream Render shuts off their fetchlands and graveyard-adjacent plays while milling them, which matters little against their library-dig engines but still disrupts their mana. Teferi is weaker here since they have few artifacts/enchantments worth bouncing and his static ability barely slows a ramp deck that wants to resolve sorcery-speed threats anyway. Prismatic Ending and March of Otherworldly Light are kept thin since their colorless permanents (Emrakul, Devourer, Eldrazi Spawn) dodge converge/exile-for-mana-value math less efficiently than Solitude or Galvanic Discharge already in the maindeck.