Undergraduate recitation/discussion session: when is it (not) counted as a credit hour?
Just add a couple more points that may be more applicable to you as a committee member.

Usually, most academic degrees granted by universities are accredited by some overseeing organizations. These organizations evaluate the school's syllabus, infrastructure, and other personal and academic factors, and determine if they would continue their acknowledgement of the degree's representativeness. You can scout around and see if your department has some of these accreditation processes, and learn more about the missions and criteria of those overseeing organization.

Second, check your school's and department's mission/value statements. When proposing a new course, these statements would come handy as a supporting point. Similarly, if your department has a good academic competency checklist, you can also refer to that list, and evaluate if, overall, your institute's degree is enabling these competencies, and if a discussion-type course can further strengthen so.

Third, understand the process of approving a course. This process varies school by school. However, most often there should be a committee (probably called curriculum and academic committee, etc.) that meets regularly to approve new courses or remove old courses. Ask if you can sit in one of those meetings and learn how the process happens. Meeting with the chairperson or secretary would also be helpful.

Fourth, if you happen to be a student representative, don't forget to use your connection to solicit students' ideas. Be very present and actively seek inputs (even it means standing out at a large lecture and ask them to fill in your online survey, etc.)

All these should give a good preparation.

Now, your question is difficult to answer because it does not just depend of school, but also is an evolutionary process of its own within each of the schools. A credit-counting discussion course might be a result of an informal journal club started a couple decades ago... likewise, a current informal discussion could be a remnant of a credit-counting course many years ago which was crowded out by expanded syllabus or was cancelled due to constant under-enrollment. You'd have to check with some more senior faculty members to understand the ins and outs. And here, knowing the school culture and history would help.