Adding a color to 8-Rack to improve a matchup or otherwise shore up holes in how the deck plays out probably means that the Modern metagame, or just your metagame in general, isnt soft enough to 8-Rack to be playing it at that moment

Advanced Search Sets Random Syntax Release date: 2008-10-02 Akrasan Squire Angel's Herald Angelic Benediction Angelsong Bant Battlemage Battlegrace Angel Cradle of Vitality Dispeller's Capsule Elspeth, Knight-Errant Ethersworn Canonist Excommunicate Guardians of Akrasa Gustrider Exuberant Invincible Hymn Knight of the Skyward Eye Knight of the White Orchid Knight-Captain of Eos Marble Chalice Metallurgeon Oblivion Ring Ranger of Eos Resounding Silence Rockcaster Platoon Sanctum Gargoyle Scourglass Sighted-Caste Sorcerer Sigiled Paladin Soul's Grace Sunseed Nurturer Welkin Guide Yoked Plowbeast Call to Heel Cancel Cathartic Adept Cloudheath Drake Coma Veil Courier's Capsule Covenant of Minds Dawnray Archer Esper Battlemage Etherium Astrolabe Etherium Sculptor Fatestitcher Filigree Sages Gather Specimens Jhessian Lookout Kathari Screecher Kederekt Leviathan Master of Etherium Memory Erosion Mindlock Orb Outrider of Jhess Protomatter Powder Resounding Wave Sharding Sphinx Skill Borrower Spell Snip Sphinx's Herald Steelclad Serpent Tezzeret the Seeker Tortoise Formation Vectis Silencers Ad Nauseam Archdemon of Unx Banewasp Affliction Blister Beetle Bone Splinters Corpse Connoisseur Cunning Lethemancer Death Baron Deathgreeter Demon's Herald

For example, if the card you discover has "As an additional cost to cast this spell, sacrifice an artifact," you can't sacrifice one of the Treasures from Hit the Mother Lode to pay that additional cost
For competitive players, the value is limited
This version of Keen Duelist captures the spirit of Commander perfectly, and the card lets you and an opponent reveal and draw cards while you trade life totals in a tense mini-duel each upkeep
Especially if youre trying to brew a deck and constantly changing cards around to find the optimal configuration