Please, go build the simplest MCP server you can that serves a prompt. Now make it dynamic by user. Now let you users share a common template. Now look at the telemetry you see on the server when someone uses the skill. Now add a flag to turn some on and off. Now imagine you are in an enterprise and you want to centrally manage all skills across the teams mapping some skills to some teams, revoke skills, force update skills, compose skills by user automatically using rules.
Please. Just try it. You can literally vibe code this in a few minutes and connect the dots.
A file on disk is static. An HTTP request-response for text is not. Build just one prompt endpoint. Now imagine dynamically injecting text into the skill as well because it's just HTTP.
You are arguing why we need web servers when we can just email text files to each other, save them on disk, and open them in Notepad. Do you not understand the power of using an HTTP server for sending text?