When I find a website I like one of the first things I look for are the contact details. I always do this when it’s a site I’m considering buying from, but I also often do it on information sites. If a site is purely informational I can understand they may not have this information but if you are selling products and services online your contact details are a must.
I want to know who I am buying from and if I can’t find any contact details or they are hidden and I have to hunt them out I wonder why. What are you trying to hide?
Make your contact details clear and easy to find. As well as helping convert visitors into customers they’ll help your rankings in local search queries.