Best Of

In addition to what @Thor
said, it is relative or subjective term.

But it also tells about the your marketing skills, your promo video, your intro video, your course description, your course image etc.

Lower the conversation rate as compared to category average, means you have to improve above items.

But it can be subjective. For example, on my one course, I get 1000 visitors, and I get 100 enrolments, I will have conversation rate of 10%. But on my second course, I get 20 visitors and I get 5 enrolments, my conversation rate will be 25%. Now I cannot really compare my course 1 and course 2 purely based on conversation rate. Because this will be misleading and will give me impression that my course 2 is more successful.

If I compare my two courses and they are at conversation rate of 5%, but my category conversion rate is around 10%. But my these two courses are the top earning courses, also, according to market insight. But still I am sure that there is need to improve the many things on my course.

So point is that, use this variable carefully and according to your situation. And you are the better judge of your situation.

Thanks.