That solution will not work as well when the interfaces have not been standardized in a way that makes it so easy to import them into a script as a library.

Coding against every subtly different REST API is as annoying with agents as it is for humans. And it is good to force vendors to define which parts of the interface are actually important and clean them up. Or provide higher level tasks. Why would we ask every client to repeat that work?

There are also plenty of environments where having agents dynamically write and execute scripts is neither prudent nor efficient. Local MCP servers strike a governance balance in that scenario, and remote ones eliminate the need entirely.