Maverick is a grindy green-black midrange deck with efficient threats like Hogaak, Arisen Necropolis and Wight of the Reliquary, so Barrowgoyf gives us a deathtouch, lifelink blocker and attacker that trades well against their creature-based plan. The extra Fatal Push cheaply answers their early Stitcher's Supplier or Scythecat Cub before they scale up. Daze is weaker here since Maverick isn't relying on tempo-sensitive spells worth countering for one mana, and Snuff Out can't target black creatures, which covers most of what Maverick plays, including Stitcher's Supplier, Wight of the Reliquary, Hogaak, Moonshadow, and Orcish Bowmasters, so it is a poor fit in this matchup. Keep Wasteland and Thoughtseize in, since denying their mana and stripping their hand remains our best angle against their grindy gameplan.