The real value isn't the format itself — it's progressive disclosure. When you dump everything into one monolithic doc, you're burning context tokens on instructions the agent doesn't need for the current task.

Skills as a pattern let the agent scan a lightweight index of descriptions, then pull in the full instructions only when relevant. Whether that's a .skills/ folder or a README index pointing to separate docs doesn't matter much. What matters is the separation between "what capabilities exist" and "how to execute this specific one."

The standardization part is mostly useful for distribution — being able to install and share skills across projects without manually wiring them up. Same reason we standardize package formats even though you could just copy-paste code.