There was an incredibly large coil-spring attached between the door and frame that caused it to automatically come slamming shut behind us. To a kid that spring wasn't a closer - it was a slammer. If you have a great-grandchild who has slammed the back door once too often, maybe it's time for you to go shopping. It does more than prevent a door from slamming shut. Quiet is just the first issue.
Safety is a factor, as well.
Lots of folks think that door closers are only for outside doors. Door closers not only help to automatically close a door and close it quietly, they also close it slowly. A door closer can quiet door activity and make a door safer. But there is another advantage to a door closer. It can reduce damage to a door.