Yes. Having someone explain something to you in a different way can be useful. Now this is course/professor dependent. If you find that you aren't learning anything by reading either the textbook or the lecture notes, you aren't morally obligated to do it.I was wondering if there is any compelling reason to read the assigned book instead of lecture notes either from the actually professor of the course you are taking or from another another source online as opposed to the book if they seem to cover the same material.
MIT has also moved the intro physics courses to something like this format. One reason for doing it was that it was how the students were learning anyway.google "peer instruction", and "eric mazur". he is a harvard professor of physics. the thing that surprised him was that even his highly motivated bright students were not really learning diddly from hie lectures.