SCORM - Class Enrollment

Summary

Is there any reason not to put the enrollment on the class rather than the course?

Content

The question I have right now is, from SCORM importing: 'can you create an enrollment on a class without making the class a course?'
and is there anyway to import a class into a course, so you don't have to create all over again?

This has been a topic we are just starting to use more and my notes all say to import Class, create Course, then create Enrollment - but do you have to create the course and if so, why?