copelmat is right in pointing out the dangers of pathetic fallacy, but I do think that examining its usage in a number of different works of literature yields very interesting results. Pathetic fallacy in some instances allows the author to suggest a mood or a tone that is opposite to the tone or mood suggested by action. One famous example is in Jane Eyre when Mr. Rochester proposes to Jane and they are both ecstatically happy. Yet that night a storm comes and a bolt of lightning splits the chestnut tree where Rochester proposed to Jane in half. This clearly foreshadows the revelation of Bertha Mason and the unnatural act that Mr. Rochester is trying to commit.
In addition to what is said above, pathetic fallacy is also important because it offers human beings one more way to begin to understand and comprehend the natural world. By projecting human thought and behavior onto elements of our environment, we make understanding it more accessible; we are comparing it to something we already know and understand. The essential question then becomes whether or not we are somehow corrupting our own understanding of the natural world by trying to understand it through our own terms and agenda rather than allowing it to stand on its own.
I think that pathetic fallacy is an important concept in literature or films because it helps to widen the reader's or viewer's scope of compassion or empathy. I think that this is even more important in children's literature, as it helps to broaden the emotional intelligence of emergent readers and thinkers. In some respects, pathetic fallacy can help to sensitize children and allow them to become more aware of their own emotional understanding. It can help parents or other caretakers to facilitate dialogue that can widen the understanding based on affect. For example, Shel Silverstein's book, "The Giving Tree," could be one example where the object of a tree was used to enhance a wide array of emotional sensitivity in the reader/ listener. This can be seen as one reason why pathetic fallacy can be considered extremely important in all art.