What is the difference between the playlist types?

What is the difference between the playlist types?

Instructional- Run of the mill playlist. For delivering instruction to students. 

Gradebook- Same as above, but also creates a gradebook on the scoring tab.

Course- Same as the previous 2 but also makes this playlist an official Course

Strand- Very similar to course playlist, but a different kind of bucket to associate standards in. Sometimes districts that use courses want an additional system to report out on that is more topical.