You are the leader. Prep cooks, servers, and bartenders look to you for guidance. A lot of new chefs coming out of culinary school will apprentice under caterers. Also, cooks without a culinary background need guidance when preparing food. The food is your baby. You don't want someone mistaking salt for sugar in the kitchen or cooking meat until its jerky.
In this biz, you are only as powerful as the last event you catered for. If you knocked high society's socks off with a magnificently prepared feast for their latest fête, you should have some good word of mouth, but if you grossly undercooked the salmon, you may be too busy handling lawsuits to spend time salvaging your reputation.