“Where is the line between art and literature/creative nonfiction?”
All literature is art, but not all art is in the form of literature.
All creative nonfiction is art, but not all creative nonfiction has to be in the form of literature. A painting of a historical event could be considered creative nonfiction but not literature.
Bechdel’s Fun Home happens to be a piece of art, literature, and creative nonfiction all at the same time. Art implies an aesthetic aspect, and Fun Home is definitely aesthetic by both its graphics and its language and literary devices. Bechdel’s graphics and story-telling is able to touch the reader on an emotional level and convey meanings that are so much more than on-the-surface and informative. Motifs, metaphors, satire, humor, the structure of the story, and the vulnerability that drips through in the story all make the reader’s experience an artistic one.
Structure is important. Structure paints a picture and creates meaning. Whether it’s the structure of the content or structure of a graphic, the structure of a comic makes the difference between it being a piece of art or just a comic strip from the newspaper. Because comic strips are usually so short and simple in newspapers, they do not have a lot of structural qualities–there is no equilibrium followed by the building of a climax, there are rarely any motifs, and the effect of the satire and humor usually last as long as the humor of a single joke would, instead of contributing to a bigger, deeper theme.
Frankly I hate getting into arguments about whether something is art or not, because meaning and beauty are subjective, making art subjective. I guess it does matter a bit that we do not define art as something it is not to avoid everyone calling themselves an artist and everything art. But the most important thing is just to sit back and enjoy the experience (what we see as) art gives us, whether others choose to define it as art or not.