Visa, Mastercard, and Coinbase are vying for dominance in the emerging market of AI-driven commerce, focusing on how AI agents handle payments. Visa and Mastercard have introduced tokenized card credentials for AI transactions, with Mastercard's Agent Pay and Visa's Intelligent Commerce leading the charge. These systems allow AI agents to transact on behalf of consumers using existing card networks. In contrast, Coinbase has launched the x402 protocol, which uses stablecoins like USDC for direct web payments, bypassing traditional card systems. This method is tailored for high-frequency, low-value machine-to-machine transactions, offering a different approach to AI commerce. Both card networks are hedging their bets by investing in stablecoin technologies, with Visa collaborating with Coinbase and Mastercard acquiring the stablecoin platform BVNK. This strategic positioning suggests that while card networks currently dominate consumer retail transactions, stablecoins are gaining traction in machine payments, indicating a potential shift in the payment landscape.