Pyrokinesis can be cast for free by exiling a red card from hand, and it answers Mishra's Factory and Faerie Conclave once they are animated. Both are key mana-sink threats that only exist as creatures on their terms. Pyroblast gives us a cheap answer to their blue spells like Counterspell, Mana Leak and Fact or Fiction, and it can also destroy an animated Faerie Conclave, which is a blue creature. Tormod's Crypt does little here, so it stays in the sideboard. Sulfuric Vortex damages us too, which is risky when Swords to Plowshares and Wrath of God slow our clock, and Urza's Bauble is replaceable with more impactful cards. Play around Standstill by developing lands and using burn on their face or Mishra's Factory rather than casting extra spells into an empty board, since any spell we cast into Standstill gives them three cards.