This is probably just "filler" content designed to give us something to do until 2.0. Since there's a lack of things to do, the content needs to be spammable with short re-enter times. The 1hr time limit is a good way to keep the same dungeon interesting and intense even if you do it over and over. I don't think every content in 2.0 should have a special reward for doing a speed run, but for the current filler content I think it's a clever way to add another level of difficulty. It requires mastering the dungeon and playing the jobs/classes effectively. You should be rewarded for it.