Affinity floods the board with artifact lands and artifact creatures like Refurbished Familiar and Baleful Strix, so proactive artifact removal and disruption matter more than our own fast mana. Undergrowth Leopard adds a second cheap body that can sacrifice to destroy a key artifact, complementing the remaining Masked Vandals, which stay in for the same reason. Mesmeric Fiend strips a key threat before they curve out, buying time to stabilize. Lotus Petal is cut since the extra explosiveness matters less than answers against an aggressive artifact-based board.