Brotherhood's End's artifact-destruction mode wipes all artifacts with mana value 3 or less, taking out Mishra's Bauble, Mox Opal, Tormod's Crypt, and Pinnacle Emissary in one sweep, gutting their mana base and threats simultaneously; note it leaves Urza's Saga and Kappa Cannoneer untouched since the Saga isn't an artifact and Kappa is mana value 6. Harbinger of the Seas turns Spirebluff Canal and Fiery Islet into Islands, cutting off the red mana Affinity needs for Galvanic Blast and other burn. Stubborn Denial is too slow against their fast low-curve draws, and Street Wraith's swampwalk is irrelevant here. Keep Fatal Push and Thoughtseize to strip their key mana artifacts and threats before they snowball.