A required update doesn't mean the game will not be on the disk. It means after Larian has to send the version to the manufacturer to make the DVDs they are still going to be fixes made up until the actual release.
But it doesn't say update, it says download the game, another bit: "Once the game has been downloaded, you can copy the game and uninstall steam if you want."
Of course if you download the game from Steam you also need the updates from Steam. It's just the way that entire reply is phrased it most certainly sounds like one needs a full game install from Steam.
