I'm starting to break out of this mentality by noticing that

1. I excelled at my exams without any strange note taking systems;

2. I remember many details down the road, even things I thought I had forgotten. For example, I needed some Linear Algebra, and I was surprised by how much I recalled after 10 years, so much in fact that in 3 days I was on par with when I passed my exam. It would have been worth it to make an Anki flashcard for every theorem?

3. In the exam I used such method I just needed much more time that when I used my minimalist note taking. So much in fact that I question the efficiency of such methods.