The biggest reason is that the other cards ahead of it have even less of an opportunity cost than Mana Crypt
Sometimes, these are commanders who offer benefits to their opponents and can fall into the group hug category
Advanced Search Sets Random Syntax Aang, Master of Elements Advanced Reconstruction Animar, Soul of Elements Archmage of Runes Armor Wars Artist's Talent Ballad of the Black Flag Ballyrush Banneret Baral, Chief of Compliance Bard Class Baron Strucker, HYDRA Overlord Because I Have Willed It Beluna Grandsquall Beluna Grandsquall Bladegraft Aspirant Blood Funnel Bontu's Monument Bosk Banneret Brago's Favor Brighthearth Banneret Bronze Calendar Bureau Headmaster Call Forth the Tempest Captain Eberhart Case of the Ransacked Lab Cemetery Prowler Centaur Omenreader Chatzuk, Mighty Guitarist (playtest) Cheap Ass Chimil, the Inner Sun Cid, Freeflier Pilot Cloud Key Collected Conjuring Commander Liara Portyr Council of the Absolute Cunning Nightbonder Danitha Capashen, Paragon Danitha Capashen, Paragon Daru Warchief Defiler of Dreams Defiler of Faith Defiler of Flesh Defiler of Instinct Defiler of Vigor Director Nick Fury Dirgur Focusmage Doc Aurlock, Grizzled Genius Dragonlord's Servant Dragonspeaker Shaman Dream Chisel Edgewalker Elderwood Scion Emerald Medallion Emet-Selch of the Third Seat Enthusiastic Mechanaut Epic Experiment Esper Etherium Sculptor Eye of Ugin Ezio Auditore da Firenze Ezzaroot Channeler Feeding Grounds Finale of Promise Fires of Invention Fleem, Goben's Creation Font of Magic Fortune Teller's Talent Foundry Inspector Frogtosser Banneret Gargos, Vicious Watcher Gathering Stone Geyser Drake
Delver was in Canadian Threshold decks, Team America decks, UR Delver decks, BUG Aggro decks, and on, and on
