The Credibility Leak
A small-business owner with an audit letter lands on your site. He sees "Tax Preparation" in the header and "EA" in the footer, and goes looking for a CPA.
The IRS licensed you with unlimited rights to represent him before the agency. Your site never said so, so he never knew.
One representation case a month lost to a less specialized firm is $30,000 a year at $2,500 a case.