Just continuing something I've mentioned before, it is really true that there really is no reason for even a small fraction of the press to be here, assuming the purpose of them being here is to inform the public about what's going on at the convention. Media members like to fret about convention coverage, as if the political parties force them all to come here against their will. Then they come here and write stories about how know news is being made here, as if they weren't aware of that fact before hand.
The best convention coverage would be CSPAN style for TV, and posting up the full text of speeches online and excerpts of them in print for newspapers. There's some place for contextualizing that journalists can do, but really not all that much and certainly not the invented narratives and expectations games.
So why are they are? Because it's the place to be.