A task status workflow is special. Rather than applying to a scene or an asset, it applies to the task of another workflow. In fact, it provides statuses for that task, letting the user know the precise progress of said task. Take for example the Basic Task Workflow below, which is provided with Producer.
All six nodes are a possible status for tasks where the Basic Task Workflow has been selected as Task Status Workflow. When the user click on a task status, a drop-down menu let them choose one of status.