on Jane Friedman site:

Asking someone to beta read for you is one of the first steps you will take toward becoming a well-paid, published, consistent writer. Because, for many of us, the beta reader process is the first time we must own the identity of: WRITER.

Owning your writer identity is the biggest mindset hurdle we face. This is especially true if you’re uninitiated and haven’t yet been published and/or paid for your work. Once you overcome this hurdle, you build up courage to reach for bigger opportunities (and pay checks) in your career.

Building up courage starts long before we are paid, published, or well-known. Building up courage happens in tiny decisions and actions, day after day, year after year. Building up courage starts the moment you realize your manuscript is polished to the best of your ability and you need to ask someone for an objective opinion on your work.