god every time this 'is it ok for adults to read children's books' discourse comes up i get so frustrated. at one end you have people fervently arguing that children's books are the superior form of literature and that adult books are 'boring' and then at the other end you have people equally fervently arguing that if you pick up a children's book after age 18 your brain will instantly rot or something
what makes something a book for children is partly the content but also largely accessibility to people who are still learning to read (simpler vocabulary, straightforward prose, etc). in terms of quality of writing children's literature runs the exact same spectrum as adult literature.
some children's books are also considered to be classic works of literature; this is not in spite of being written for children but generally because they were written for children. the target audience is an essential part of the medium.
being able to write a well-structured book with well-crafted prose and compelling themes which can be enjoyed and understood by children is a skill in and of itself. reading a book and breaking down the themes, etc, isn't inherently less of an intellectual exercise when it's a work of children's literature.
