Within the game itself, Gold is used to either:
All heroes have a specific Gold stat that indicates how much gold they start with. Additional Gold can be gained either by exploring Dungeon tiles, completing certain quests, or playing certain cards.
Gold is one of the coins used as the main form of currency in the Kingdom of Armello, and are at the center of all trade both fair and dubious. As masters of mercantilism, the Rat Clan has made the acquisition of this material a particularly large part of their society, and Bandits will often go to great lengths to line their pockets with a glittering prize. The Rabbit Clan likewise consider it a precious metal for their artisans, with many crafted items and rings being carefully made from it.