1. Public speaking. You don’t have to say anything if you don’t want to. Other than saying your first name, it's rare you would be asked to say anything more. Ever. Unless, of course, you'd like to speak more. People speak, if and when, they are ready. And that comfort level varies from session to session.
2. Cost effective. That's another word for cheap. Group is often 1/3 to 1/2 the cost of a same time individual session.
3. Flexibility. Group is flexible. Missing sessions may be less disruptive to you and your therapist in a group setting. Also, don't worry about loss of contact with a valued therapist as most often a person starting a group also continues with individual sessions.