By that logic, most everything other than a club to the head is "just stories". Hume points out in a Treatise on Human Nature that most of how we interact with the world is through a coherent hallucination provided by sense organs that tell very narrow stories, but when stitched together form a cohesive whole. You're almost doing the equivalent of saying that gravity is "just a theory".

Society is a story, not a chemical reaction. People like the story of money because the stories that had gold coins or barter sucked a lot worse.