Every role in a Strategy makes one choice: live directly on the project it's instantiated into, or get a dedicated workspace of its own, nested underneath it.
A role that only watches and hands off — polling somewhere external, noticing something, and leaving a note for a different role to act on — rarely needs its own space; it has no code of its own to check out.
A role that actually makes and commits changes almost always needs its own dedicated workspace, so its history and checkout stay distinct from whatever its siblings are doing at the same time.