Izzet Spellementals wants to chain cheap cantrips and land Hearth Elemental or Eddymurk Crab at a discount, so Duress proactively strips a key piece like Prismari Charm or Traumatic Critique before it can disrupt your board. Ghost Vacuum exiles cards from their graveyard, slowing the cost reduction on Hearth Elemental and Eddymurk Crab while also denying value from their own Ghost Vacuum. Dark Knight's Greatsword is too slow and clunky when the opponent has cheap bounce and removal like Prismari Charm and Burst Lightning to blow you out on the equip. Desolation Prowler's life-payment pump is risky against a deck that can flip Traumatic Critique or Burst Lightning at your face, so it comes out for the more proactive disruption.