Eldrazi Tron relies on the Urza's Tron lands (Urza's Mine, Urza's Power Plant, Urza's Tower) and Eldrazi Temple to power out Ugin, Eye of the Storms and Karn, the Great Creator, so Break the Ice is excellent at stripping key nonbasic pieces of their manabase. Ghost Vacuum answers their graveyard recursion potential and can eventually reanimate a threat for us. Vexing Bauble punishes some of their zero-cost artifacts like Expedition Map's activation is not a spell so that doesn't apply directly, but it still counters any truly free spells they might have; more importantly it's a cheap artifact that dodges Meltdown-style sweepers from their side. Consign to Memory does hit their many colorless spells (Devourer of Destiny, Sowing Mycospawn) but we prioritize land disruption to deny them Tron/Eldrazi Temple mana before they can deploy threats.