Based on Act 3 Scene 1, what does Ophelia's presence do for the audience?

Ophelia's comments on Hamlet's state of mind add a layer of insight into just what kind of man he was and what kind of mind he had before the appearance of the Ghost, also adding to the increasing sense that while he is essentially both admirable and honorable (not to mention intelligent), he is profoundly flawed. In other words, he is, in the classical sense, a tragic hero.