It has nothing to do with Agents/LLMs which is why it's not called "Agentic Payment Protocol."

It's an API for making purchases instead of interacting with a website of unknown flow.

The text literally starts with:

  > We believe agents will become an integral part of the internet economy, and they need the ability to transact with businesses and one another. 
  > MPP provides a specification for agents and services to coordinate payments programmatically, enabling microtransactions, recurring payments, and more.