Teaching is a two way process
Seeing a video or listening to an audio is not as effective as directly listening to a lesson delivered by a teacher in a classroom. What is the reason? My answer to this is that teaching is not a one-way process. Just going on telling the lesson is not the purpose of teaching. That is why many people say teaching is a two-way process.A teacher should keep this in mind and prepare the lesson plan. A teacher may be an expert in a language and may have an excellent vocabulary. But the lesson he delivers is to be understood by a common student. So a teacher should think about the level of the student and teach using simple words and normal grammar. Then only a perfect process of teaching will take place.
I hope all the learned members of this site will agree.