Boros Dwarves is an aggressive equipment-based deck, so Elegy Acolyte's 4/4 lifelink body is a strong blocker that stabilizes the race against their small equipped creatures. Deep-Cavern Bat gains life and can strip a key Equipment like Leyline Axe before it turns a Dwarf into a serious threat. Sunset Saboteur and Forsaken Miner are both fragile bodies that can't profitably block or trade with their aggressive curve, and Forsaken Miner's inability to block is a real liability in a race we want to slow down.