AI agent payments are transitioning from proof-of-concept to infrastructure, with x402 and MPP merging into an open, commercialized framework. Facilitators, who manage signature keys and spending strategies, could become pivotal in the payment ecosystem. Stripe MPP has pioneered the coexistence of stablecoins and fiat within a single protocol, while Visa and card networks maintain an advantage in coverage and compliance. In the short term, card channels will dominate, but stablecoin acceleration and cross-chain collaboration are expected in the long term. Key challenges include identity verification, compliance, cross-chain integration, and vendor coverage, with timing and trust as critical factors.