While it's efficient, it makes certain tasks more difficult. Let's say you want to bottle a few dozen magnums, for example. You can't call in a bottling truck just for that, but you can uncork some 750 ml bottles and pour 2 into each empty magnum bottle ("marrying bottles", as bartenders would say). But how do you cork them back up?
First, a quick laugh re: corking bottles (NSFW if your coworkers are uptight people with no sense of humor): http://www.hulu.com/watch/19187/saturday-night-live-cork-soakers
And now, this is how it's really done: