My subjective opinion is that a reader would learn more from a person that went to discover a new topic and wrote down the steps and knowledge acquired along the way. The reader is essentially taking the same steps, learning the same things. If however an expert would write about the same topic, she will have hard time to follow the same pattern.

I believe that J.K. Rowling used the same pattern for her Harry Potter books. She started writing them for children and then each book followed the same kids to their adulthood.