It can be. Mostly they're used for things like my pants and my boots - securing the item in place or sealing it faster than trying to lace it, and with more security than, say, Velcro.

_{[ He looks up at Sam when he brings the zipper back up and sticks his tongue out slightly at him, reaching up to brush his fingers behind the other's ear. ]}

It also makes them much, much easier to get off. You know, for when you're in a hurry.