Unless you live in a cave, you probably see a lot of faces over the course of a day.
Let's face it, intentional or not, good or bad, you make judgements based on those faces.
Great photos of the people in your business can be inviting and give visitors someone to recognize. They can also add personality and style to the faces, something people can identify with.
Whether you're looking for a job, or marketing for the one you have, a great headshot can create a sense of trust and credibility. You don;t want to be on the other side of that equation!