Duress proactively strips their key noncreature engine pieces like Ajani Resolute, Case of the Uneaten Feast, and Lunar Convocation (or a removal spell like Erode) before they generate value. It can't take their creatures, including Liliana the Faultless, so it is only part of the plan. Day of Black Sun sweeps their cheap lifegain creatures (Hinterland Sanctifier, Enlightened Confidant, Starscape Cleric) which fuel their whole plan. Shoot the Sheriff contributes little against a grindy lifegain deck, and We Say Thee Nay! is awkward since much of their value comes from creatures and triggered abilities rather than countered spells. This is a grindy matchup where disrupting their engine pieces matters more than racing.