How is a root system different from uploading my files to Claude?

Uploading works, and for a single document it's the fastest thing you can do.

What you get is a copy that sits still. The version you save on your computer tomorrow isn't the one you uploaded, so you attach it again, and again.

A root system is live. Claude opens the current file, changes it, saves it, and the change is there next week whether or not you remember to attach anything.