You remember "Hanging Up"--Diane Keaton, Meg Ryan, Lisa Kudrow, Walter Matthau (2000)? Marketed as a comedy. The clips in the ads were funny. Actually, they were the only funny moments from the movie. A lot of people ended up hating a not-bad film because it wasn't what they'd expected.
Seems like more cover art is this way. Looks like comedy or even chick lit, but isn't so much. Clearly, the marketing idea is to sell via mass appeal, but I wonder about word of mouth (and reviews) thereafter.
Not that this is a sign of the apocalypse. But like most folks, I pick up my next read based on the mood I'm in and whether it's a match. Hm. Maybe content-consistent cover art doesn't matter for splash, but I bet it does for legs.