Answer:
The sound won`t echo as much, so you can get finer and more exact sounds. Since the singers are constantly noting the others` part, they need to be lined up, which practicing in close quarters allows. This was something I was also taught in orchestra, even though I didn`t think it really made a difference. The teacher would have us sit next to each other as close as humanly possible without getting hit by a bow or elbow. The teacher insisted that the sound would be more unified and have a smoother flow, plus we would all hear each other and pick up cues better.
(this is what i wrote for my paper lol)
