I think it's far too early to assume assume the "swelling" is a net harm or that preventing it is good in the long run.

Perhaps it serves an important protective or regulatory purpose which we haven't yet identified, because we still know so little about sleep and consciousness.

An analogy: There are lots of systems in your body that try to prevent and deter you from casually walking on a damaged leg, and we can override some of them with various external drugs, but that doesn't necessarily mean it's a good idea.