The Z-Wave+ property (and others) is derived from information about a node provided after joining the network. A controller being accessed over the USB serial connection doesn’t provide this information. From the HA point of view, there’s nothing special about the serial USB controller, and from the driver API all nodes provide the same properties, it’s just some of these properties are never set for the controller so they default to some value. It would require special handling by the application to ignore these fields for controller nodes.
In fact, zwavejs2mqtt does this and will not show these fields for the controller in a future release. Hopefully the HA UI will follow suit to avoid this confusion.