None, because it’s not a real department, and has as much legal meaning as any made up department you and me can think of. But if course if Trump acts as if it’s real and listens to it’s opinions (which have the same legal weight as any private person’s opinions), then it doesn’t matter it’s not real.
To make it more specific I guess, what’s the problem with that? It’s like having a “people living on boats” and “people with no long term address”. You could include the former in the latter, but then you are just conveying less information.