Need? No, Want? YES!
The biggest reason is that (as of this writing) up to 48% of all surfing is done by people on computers that are not their own, specifically employees surfing on the company computer. They most likely do not have their private email set up, so to email you would mean to use the company email. Many people are not allowed or are concerned about privacy.
Another reason is that we see many of the forms are completed past or even way past normal business hours, so with a contact form, you will have someone who may not want to disturb you at 3 AM for an inquiry, they don’t seem to mind completing a form at that time.
By providing a contact form, people can send you the information you want from any computer and at any time. So it is something that we suggest very strongly if the goal of the site is to gather a lead or customer information.