Honors Courses but not in Honors Program?

Is it possible to take honors courses without being in the program?

Also, why be a part of the program other than getting priority for registration and having something to put on your app for grad school?

There are multiple types of honors courses. If you are referring to an honors seminar, which is a 2-unit course that usually meets once a week, then I don’t think you can take it without being an honors student. If you are talking about honors sections, which are supplementary courses to regular 4 unit courses, then I believe you can still ask for admission based on your interest in the subject. As an honors student myself, I really enjoy the program mostly because of its priority of registration perks. Other than that, you essentially surround yourself with hard-working students and get a deep understanding in a variety of subjects. As someone who took AP classes in high school mostly because of the rigorous environment, I appreciate the honors program as it offers yet another opportunity to study and discuss topics with students who are at a high level of critical understanding. You also get another set of honors advisors who have more of an open availability to your general questions.