Dimir Midrange plays expensive, powerful payoffs like Kaito, Bane of Nightmares and Enduring Curiosity that our deck struggles to race through combat once they stabilize, so countering key spells on the way down is crucial. Disdainful Stroke handily counters Kaito, Bane of Nightmares and Enduring Curiosity, since both are mana value 4. It can't hit their cheap creatures like Floodpits Drowner (mana value 2), and a Kaito put onto the battlefield with ninjutsu is never cast, so it can't be countered either. Spell Pierce taxes their noncreature spells, namely their removal and a hard-cast Kaito, early when they're tapped out developing mana. Impractical Joke is weak since most of their early creatures (Dream Beavers, Floodpits Drowner) aren't profitable 3-damage targets relative to our tempo plan, and Vibrant Outburst is replaced by more proactive disruption. Stay aggressive and use the extra interaction to protect our clock from their removal-heavy suite.