Jeskai Revelation decks lean heavily on blue spells like Jeskai Revelation itself, Divide by Zero, Pop Quiz, and It'll Quench Ya!, making Mystical Dispute a cheap, efficient counter that costs only {U} against their key cards. Abrade answers Thor, God of Thunder's 5 toughness only partially but reliably kills smaller threats like Gran-Gran or deals with their Tablet of Discovery. This Town Ain't Big Enough and extra Boomerang Basics are too slow and card-disadvantageous against a deck full of countermagic and card draw, so they're cut for more proactive disruption.