Boros Dwarves is a low-curve equipment aggro deck full of cheap creatures like Dwarven Mauler and Warden of the Inner Sky, so Day of Black Sun sweeps their board efficiently in the early-to-mid game while their equipment falls off with no bodies to carry it. Deep-Cavern Bat trades well with their small creatures, gains life against an aggressive clock, and can strip a key Equipment or threat from hand. Rapid Rescue and Wistfulness are too slow and reactive against this fast aggro strategy, so they're cut for more impactful disruption.