@thehomme said it well, “I think Materials and Shaders are difficult to ‘teach’ in isolation”.
Being a more technical topic, there is so much to teach, squeezing too much into a single “beginner” course would overwhelm too many new students, while not satisfying others.
It’s always a balancing act to get it right, and it’ll never be right for everyone.
Different teachers have different teaching styles. Remember your school days? We all had our favourite teacher, and one teacher we didn’t like so much.
How the lessons are taught is obviously important, but I’d argue the content more so.