Is it good to learn from a diary about World War II?

It is only one person writing and talking about what happens each day out of Anne's life with her family in hiding. I disagree that a diary is not mainly focused on World War II. Why? Because she is talking about the characters that are in hiding with her and why her family is in hiding. The reason they're hiding: she is a Jew plus her family and the people that she is living with. Yes, there might be little pieces to what is going on in the outside world, but not in really good details to visualize what is happening because Anne's family is in an attic/business place so that they don't see what is happening in the outside world.