First, they’re just not very well designed fonts as regarded by typeface and graphic designers (Comic Sans more-so over Papyrus).
Second, they’re both classified as Display Fonts, that is, they were designed with the intent to be mainly used in a very limited fashion, say in title or poster work, logos, blurbs, or some othe stylized manner — not in large bodies of text for general reading, like articles, websites, email, books or any other form of formal writing where the style lends itself to readability, legibility and other more pragmatic reasons when setting type for compact communication takes precedence (Although despite Comic Sans is a casual font, aping the hand lettering in comic balloons, which is a narrative, rarely does the typeface match the tone of anything else, mainly because of the strong association to the medium of its namesake).
Third, they’re not just overused, but abused because of my second point above. It’s hardly snobbery or hipsters bemoaning them as inferior; it’s that the computer revolution has made these more pedestrian and ubiquitous typefaces wholly available and accessible to those with only a handful of pre-installed fonts that came with their OS. So when they’re bored of Helvetica and Times, these feel more fun or novel in comparison.
In graphic design and typography, there’s a time and place for almost any font design, however Comic Sans (being fairly new on the scene) and Papyrus offer very rare instances, even if used ironically, now that the stigma attached to them has irreparably damaged their reputation. So much so, that for a professional designer to use them would draw far more attention to the decision to use such a infamous font than any typography usually deserves, even if it seems a perfect fit otherwise. So it’s avoided.
Two recent examples where one surprisingly worked for me, and where one was used that surprised me because of the dissonance between the font used and the much-hyped state-of-the-art filmmaking:
Drive and Avatar, respectively.
The smart usage of Mistral (another “kitschy” font, overused almost as badly before Comic Sans and Papyrus overthrew it) for Drive in hot pink over the moody, violent tone of the film works on some semi-ironic, tonal level which ironically was nixed in favor of your typically trite, bold and action-y looking font when the movie gained critical acclaim and I’m guessing was re-branded for the rental/bluray market. Too bad, it was an interesting and bold choice, and made it stand out, rather than detract, or even worse, blend in with the title work of far more mediocre films it’ll now share the shelves with.
As for using Papyrus for the title of Avatar, well, I’m at a loss. Whatever your feelings on the film itself, it was a remarkable technological achievement in visual effects and art production. To go to such great lengths in design and technology and chose Papyrus, as is, for the title logo is utterly baffling to me.
So yeh, I like fonts. They’re the clothes of what you’re trying to say.