The goal is totally different!
Pretest was meant to test the knowledge of the trainee before starting a course, and based on the Pretest score be able to execute actions. Those actions could allow the trainee to skip parts of the course. Those pretest slides for that reason have a lot of limitations: they have to be in sequence at the start of the course, they will disable all navigation, you cannot retake the test etc. The results are stored in specific system quizzing variables that you can access.
However I have blogged multiple times about creating Knowledge slides, using default question slides but it was a bit cumbersome Those are slides that are not scored at all, just meant to keep the trainee engaged by putting some questions all over the course. They do not have to be in sequence at all, they will not prevent free navigation etc