A professional bio and headshot are often the first impression a client or employer will have of you. Take advantage of the opportunity to introduce yourself and influence their impression while you have their full attention.
Yes, you need a headshot
I am often asked whether lawyers really need to use a headshot in their marketing materials, because they feel slightly self-conscious about including their photo. My response is
Professional Headshots and Bios is a post from the law practice blog: Lawyerist