Thats because many rare (or higher) cards can hold significant value, and may even rise in value as the years pass
Sea Gate Restoration / Sea Gate, Reborn Sea Gate Restoration is one of the best bolt lands: a modal double-faced land that essentially doubles your hand when its front face resolves
But when Charizard is printed with a stipulation, or when it's given additional things to make it stand out, the value also skyrockets
This has synergy in decks outside of equipment decks, especially ones where putting counters on things or tapping things draws you cards
This means youll probably not be pinching Emergent Ultimatum with any consistency
Matzalantli, the Great Door / The Core This feels better than the often underrated Growing Rites of Itlimoc, and its colorless