-You may line to lectures more actively if you get to choose when to listen. Sometimes classes are scheduled at hours (often the morning), which are simply unideal; at a point where you lack the energy and concentration to focus at all. I like being able to choose when it is that I listen because I know that by setting aside the time for it I will actually be awake.
-I like being able to pause and continue. You can listen to lectures in between classes or while you have small gaps, I seriously feel like it helps me feel more productive.
- You must have self discipline. Without this it is easy to forget about the course and continue the course imagining that you only have 4 'actual classes'
-Some people like more structured class environments
*This is all for online courses at 'actual' universities.