A cohort is not a crowd
An online course is different from an open webinar in one important way: it has a limit that matters. Sixty people might enjoy a talk; only twenty might get real feedback on their work, or a seat in the live session, or attention you can actually give. A registration page for a course has to respect that ceiling, not just collect names.
So the useful page here does three linked jobs. It tells a prospective learner what the course is, it takes a name and email as a genuine place claim, and it stops accepting sign-ups once the class is full. The number on the page is the number of people you can teach, and that is what makes the list trustworthy.