Mono-White Initiative is loaded with Chalice of the Void and Thalia effects that tax or lock out our spells, so we want efficient, low-cost interaction and a fast clock rather than card disadvantage from discard spells that get taxed by Thalia. Dauthi Voidwalker is an evasive, cheap threat that dodges their ground-based blockers and pressures their life total quickly. Fatal Push cheaply answers Thalia, Guardian of Thraben, Anointed Peacekeeper, or Seasoned Dungeoneer before they lock our board down. We trim slower disruption since Chalice of the Void can blank our one-mana spells if left up against X=1, so proactive speed matters more.