Prestige...
The number of stripes is useful to identify the person in charge and it can also show his or her qualifications. If you need to speak to the person in charge you look for the one wearing four stripes; it is no big deal.
In the States even someone flying a light aircraft gets four stripes, where in Europe he or she may have just three.
One of my helicopter pilot friends, a talented photographer, presented me with a very nice digital photo where I was posing by my airplane. I was very pleased with it until I noticed that I was shown wearing 5-bar epaulettes! Jealousy is such a sad emotion, really...
Sometimes I would get an ID50 ticket that identified me as CPT So-and-so. One day the woman at the check-in desk asked me if I was in the army, since I was down on her list as a "Captain". I just laughed: over 50 and still a Captain, three up from the bottom? Way to go!