There is a difference between a workspace and directory. In short a workspace has extra data set in the settings while a directory does not. Here is detail for each:
A workspace uses this icon.
A workspace has at least one of the following set:
When you go to a directory and set any of the above items the directory is converted to a workspace.
A directory uses this icon.
A directory inherits the parent workspaces' permissions and team. Inherited permissions will not be shown on the users access tab.