Dual ink cards require a deck to have both colors in the deck in order to be useable, but meeting this requirement lets you unleash some exclusive cards in your deck that make it worth combining colors
Magic Origins had Goblin Piledriver (a bigger deal at the time), the enemy-colored painlands, and Knight of the White Orchid
This way, even if you have rad counters and are low on life, you still have some hope to survive to your next turn
Only 11 exist in PSA 10 condition, one of which sold on ebay in October 2020 for 150,000$
Pithing Needle only costs one mana, letting you get it down on the battlefield as early as the first turn so your opponent never has a chance to use the card you named

Volcano" #847 "Darkfire Soldier #2" #848 "Kiseitai" #849 "Cyber Falcon" #850 "Gamma The Magnet Warrior" #851 "Flying Kamakiri #2" #852 "Harpie's Brother" #853 "Grand Tiki Elder" #854 "The Masked Beast" #855 "The Earl of Demise" #856 "Boneheimer" #857 "Flame Dancer" #858 "Zombyra the Dark" #859 "Earthbound Spirit" #860 "Embodiment of Apophis" #861 "Ancient Lamp" #862 "Amazon Chain Master" #863 "Thunder Nyan Nyan" #864 "Injection Fairy Lily" #865 "Dark Magician" #867 "Executor - Makyura" #868 "Viser Des" #869 "Amazon Sword Woman" #870 "Amazon Archers" #871 "Des Volstgalph" #872 "Toon Dark Magician Girl" #873 "Gilford the Lightning" #874 "Mystical Beast Serket" #875 "Cyber Harpie" #876 "Lightning Conger" #877 "Exarion Universe" #878 "Legendary Fiend" #879 "Gadget Soldier" #881 "Nuvia the Wicked" #882 "Masked Beast Des Gardius" #885 "Red-Eyes B