Some people say it's already the AI era, so why is the currency used by AI Agents still USDC? Let me give you an example: The width of SpaceX's booster, why is it only as wide as two horse butts? Back in the day, carriages needed horses to pull them. To make it easier to pass, the tracks for two-horse carriages became the roads. As things developed, this became the minimum road width. Ancient Roman chariots (two horses side by side) had a wheel gauge of 4 feet 8.5 inches (1435mm). The lineage goes like this: Roman road ruts → European carriages → British trams → British railways (Stephenson) → American railways → Global standard → (In 1937, the International Railway Union set 1435mm as the standard gauge) The width of the U.S. space shuttle rocket boosters (also indirectly determined by this gauge because they had to pass through railway tunnels). usd → usdc → For now, it seems to follow a similar path.