diaries?

Bringing diaries to class? in language class, yes. I can see how it can contribute to the lesson. but if in literature class? I don’t know how. Can a diary be considered as a literary work? It is true that from diary we can learn something, there is moral values in it.. but somehow I find it difficult. Maybe I need to sit and really look close on it if I want to bring it in the literature class and of course not Kafka’s type of diaries. Because it is too confusing.