Izzet Affinity runs Force of Will, Force of Negation, Cyclonic Rift, Sink into Stupor, and Lorien Revealed, so Pyroblast is live to counter their Force of Will/Force of Negation or destroy a resolved blue permanent. Disruptor Flute naming Karn, the Great Creator or The One Ring makes those spells cost {3} more and stops their activated abilities, taxing their most critical engine pieces. Chancellor of the Annex is a clunky 7-drop that doesn't pressure their colorless-heavy prison shell fast enough, and Chrome Mox is cut since we favor more disruptive sideboard cards over raw acceleration in this grindy matchup.