So my eldest son, who is 8, loves reading biographies. But most of the biographies he checks out from the library are in manga form. He's read about John F. Kennedy, Babe Ruth, and Honda founder Soichiro Honda—all in manga form.
Since he loves cars, he really, really liked reading about Soichiro Honda. The manga actually taught him a lot about engines and how they work. It's a shame that some people look at comic books and somehow think they can't be educational or intelligent.