Yea you really have no idea how mmo content works. Usually in small patches they will add little things like the map locations with each patch, usually the stuff that has to be interweaved into whats already there, usually menus and ui stuff (which is what is present in the video) but just have it set to not show yet . Then they add the expansion content such as new areas, items, ect when its close to the release date or on the release date, even if you dont have the expansion pass you will still get the massive update as you will still need the files to see other players with the new gear. The reason why the pass is only like 9mb is because thats just to unlock the the expansion which will come in the update patch. Not on the disc. Its common for mmos to do it like this.