Boros Moxite fields a wide array of small creatures like Kor Skyfisher (2/3), Glint Hawk (2/2), and Sneaky Snacker (2/1), so Fiery Cannonade's 2 damage sweeper can clear multiple threats at once, though it won't touch Kor Skyfisher's 3 toughness. Nihil Spellbomb exiles their graveyard to blank Pursue the Past's flashback, and it also stops their Sneaky Snackers from returning, since that trigger works from the graveyard and needs the card to still be there. It denies general recursion value as well. Alms of the Vein and Vampire's Kiss are low-impact life swings against a deck with its own aggressive clock, so cut them for proactive removal. Red Elemental Blast stays boarded since the opponent's only blue cards are the Sneaky Snackers, which is too narrow a target to justify a slot.