Workspaces allow you to give Chrome permission for read / write access to given folders. You just set it once per project and then Chrome remembers.
Basically, you can press "ctrl S" for save, straight from the dev console. In FF, you have to manually designate the save location each time. It may seem like a small thing, but it's an entirely different workflow.
For frameworks that don't use plain stylesheets, it may not be useful.