If you pay to flip it face-up, it defaults to the front face of the card

Chaotic Ruhan | Commander | Matthew Lotti Commander (1) 1 Ruhan of the Fomori Creatures (14) 1 Aegar, the Freezing Flame 1 Arashin Foremost 1 Calamity Bearer 1 Combat Celebrant 1 Cyclone Summoner 1 Flamekin Herald 1 Halvar, God of Battle 1 Kediss, Emberclaw Familiar 1 Koll, the Forgemaster 1 Raiyuu, Storm's Edge 1 Realm-Cloaked Giant 1 Selfless Samurai 1 Stoneforge Mystic 1 Stonehewer Giant Planeswalkers (1) 1 Jeska, Thrice Reborn Instants (15) 1 Chaos Mutation 1 Chaos Warp 1 Cyclonic Rift 1 Jwari Disruption // Jwari Ruins 1 Kazuul's Fury // Kazuul's Cliffs 1 Order // Chaos 1 Psychotic Fury 1 Resolute Strike 1 Response // Resurgence 1 Sejiri Shelter // Sejiri Glacier 1 Shelter 1 Slip Out the Back 1 Temur Battle Rage 1 Unleash Fury 1 Valakut Awakening // Valakut Stoneforge Sorceries (13) 1 Distortion Strike 1 Divine Reckoning 1 Fire Giant's Fury 1 Irenicus's Vile Duplication 1 Mystic Retrieval 1 Open the Armory 1 Promise of Loyalty 1 Sea Gate Restoration // Sea Gate, Reborn 1 Seize the Day 1 Single Combat 1 Slash the Ranks 1 Slip Through Space 1 Steelshaper's Gift Enchantments (7) 1 Duelist's Heritage 1 Fiery Emancipation 1 Giant's Grasp 1 Mantle of the Ancients 1 Security Bypass 1 Steel of the Godhead 1 Unquestioned Authority Artifacts (18) 1 Arcane Signet 1 Assault Suit 1 Azorius Signet 1 Champion's Helm 1 Cursed Mirror 1 Ebony Fly 1 Embercleave 1 Helm of the Host 1 Lightning Greaves 1 Meteoric Mace 1 Obsidian Battle-Axe 1 Robe of Stars 1 Sol Ring 1 Swiftfoot Boots 1 Talisman of Conviction 1 Talisman of Progress 1 The Reaver Cleaver 1 Two-Handed Axe Lands (31) 2 Island 3 Mountain 3 Plains 1 Adarkar Wastes 1 Arid Mesa 1 Battlefield Forge 1 Cascade Bluffs 1 Flooded Strand 1 Hall of Heliod's Generosity 1 Hallowed Fountain 1 Inspiring Vantage 1 Mystic Gate 1 Plaza of Heroes 1 Raugrin Triome 1 Rugged Prairie 1 Sacred Foundry 1 Scalding Tarn 1 Sea of Clouds 1 Seachrome Coast 1 Shinka, the Bloodsoaked Keep 1 Shivan Reef 1 Slayers' Stronghold 1 Spectator Seating 1 Spinerock Knoll 1 Steam Vents 1 Training Center Ruhan of the Fomori needs only three hits to spell doom for an opponent

The reason why theyre so valuable though, is because theyre all artifacts, you can play a land and one of these Mox on your first turn, giving you access to at least two mana for free on your first turn
Considering how flexible it is as a removal spell, you could even say that its absence from most decks is unexpected