Affinity floods the board with artifact creatures (Refurbished Familiar, Utrom Monitor, Baleful Strix) and artifact lands, so Ancient Grudge is premium removal. Note it cannot destroy their indestructible Bridge artifact lands (Razortide Bridge, Goldmire Bridge, Mistvault Bridge), and it can't hit Glint Hawk or Kor Skyfisher since those aren't artifacts. It does answer Utrom Monitor, Refurbished Familiar, or Giant's Boulder cleanly, with flashback for a second use. Spellstutter Sprite comes in to counter their cheapest spells like Dispatch or Glint Hawk early. Writhing Chrysalis is cut since its 4-mana body is too slow against their low curve of 1-2 mana threats, and Bitter Reunion's card filtering doesn't address their board presence. Keep Thraben Charm for its scaling damage mode against their small creatures and its graveyard-exile mode is irrelevant here but the removal mode is strong against Glint Hawk and Kor Skyfisher.