You're an expert in your field. You know what you're talking about. You have a great idea that can fill an overlooked knowledge gap in your industry.
You can work with a book coach on your non-fiction book for several reasons:
To codify, document, and brand your unique professional vision
To formally establish yourself as a thought leader in your field
To book more meetings
To secure more speaking opportunities
To earn more media coverage
To spread more social media proof
To sell more products or services