Looks are important. In training seminars I have this conversation with many people who argue that doing a good job is more important than looking impressive. While I agree with this in principle, I do feel that customers have a greater sense of confidence if you and your staff look the part. Going into a shop or restaurant and being served by a dishevelled member of staff gives the impression that they don't take their job seriously and, by association, they don't really care about the customers.
Imagine two electricians coming to your home to fix a fault. Electrician number one is wearing a neat, pressed uniform and carrying a tidy toolbox. He is well groomed and looks the part, which inspires confidence. The second electrician arrives wearing a crumpled pair of dirty over-alls, with pockets full of tools and a cigarette hanging out of the corner of his mouth. Both electricians can be equally good at what they do, but it's far more likely that the first one will be invited back again because he looks more professional.
Looking the part shows that you want to impress your customers. You care about your appearance and you want your customers to be impressed. The same principle applies to company vehicles, the workspace, even advertisements and promotional material. It's all about looking the part. That is, after all, what your customers are expecting.