It inspires more such observations that Agatha H. and the Airship City, because that was closer to the webcomics -- sometimes one panel of Girl Genius, one paragraph of Agatha H. Still, even that one had its touches.
Webcomics, or any form of comic strip/book art, have traits like a movie and traits like a book. One movie-like one is the objective POV -- except for thought ballons, which Girl Genius doesn't use, and even those are not a tight POV -- you only get the direct thoughts, explicitly labeled as such, and nothing else is seen from the character's POV unless you get into some really interesting tricks. Agatha H. is told in a fairly neutral omniscient point-of-view, the narrators making themselves clear in the narrative once (to explain that character was indeed one of the in-universe writers of the textbook that Agatha H. is presented as), but you do get into a lot of character's minds, however briefly, and it's not enough to present a scene without showing us the backstory that would make clear what is hidden, you have to keep to the points-of-view that would reveal nothing of what is hidden, and not make it obvious that they are being juggled to conceal.
Though when you do want to backstory, the prose has its advantages in that you actually can exposit in prose. Comic forms, like movies, have conceal in some kind of prose. Hummm-- or use footnotes. Girl Genius, however, doesn't. Agatha H. does, when the backstory wouldn't fit neatly into the story. (Some of them are just comic bits, and quite funny, to be sure.)
It also lets you get into the characters' thoughts. It's amazing how much can be implied by good artwork and good dialogue, but there's nothing like prose for letting complicated thoughts be expressed clearly.
Or emotions. No matter what expression you draw for the character, "an expression of blank terror" will convey less about what the face actually looked like, but more about what the character felt.
And then there are names. A character can go panel to panel for time without end being identified only by his appearance, but needs some handle in the story. Some writers go for awkward circumlocations, but the Foglios dosed large number of fan speculations by naming a character who appeared a lot, nameless, in the comic.