I mentioned that I had just read Fun Home (which he and his wife both really enjoyed -- he was there with wife and daughter) and that I thought many of the really nice literary moments in it were the spots where text and image were coming at the same idea from different angles, or were saying completely different things that related in some way. And I asked him if he thought that there were any kinds of story that were particularly well- or ill-suited to that kind of story-telling.
He agreed that the interdependent bits were really interesting, and that that's something that's really unique to comics. He said that it becomes really important in stories with a lot of interiority, that are largely about characters' thoughts and emotions. When you have a textual script that tells most of the story, it frees the pictures up to do a lot of commenting on the events, reference related events in the story, set mood, and so on. (You do have to be careful not to overdo it with the text and move into the realm of illustrated story rather than comics, though.) He also talked about meeting Alison Bechdel and talking to her about how she was discovering all the neat ways of being literary specific to comics, and that was pretty cool.