(Well, a good textbook or expository webpage is more than just proofs and definitions, but wording quibbles aside---)
I don't believe you. There are many unfortunate people who suffer from cognitive disabilities such that they can't learn (e.g.) calculus from a book, but if you're reading this site, you're almost certainly not one of them.
People are different.
As far as I see around, there are people with various optimal bite sizes.
For something I do want to consume in entirety, I prefer long-form writing; there are people who prefer smaller-sized pieces or smaller-sized pieces with a rare chance to interrupt and ask a question.
I learn better from text; there are people who understand spoken words better. Spoken words have intonations and emotional connotations (and often there are relevant gestures at the same time); text reading speed can be changed without any loss.
So, I wouldn't discou...
If it's worth saying, but not worth its own post, even in Discussion, it goes here.