Jund is a creature-dense deck that goes wide with cheap threats like Gene Pollinator, Greedy Freebooter, and Callous Inspector, so Ultima gives you a second full board wipe to reset against their go-wide plan while Day of Judgment stays in. Torpor Orb turns off enters-the-battlefield value from The Sackville-Bagginses and Biotech Specialist's Lander creation. Rest in Peace cuts off Lively Dirge's reanimation plan. Countermagic like Three Steps Ahead and No More Lies is weaker against a low curve of efficient creatures, so trim them for proactive sweeper density.