On top of that it makes work of TA easier. Everyone works more or less on the same problem, be it programming assignment, quiz, etc. If there's a new question TA most probably remember what was in the last lectures and what are the common issues students are having this week.

Same for me.

I also find the assignments/exercises on the courses are first class and that's where a lot of the learning comes in especially when backed up by discussion forum activity from other students. Watching the videos on their own doesn't really appeal to me.