The photo itself was treated for print -- my prints are 300dpi, which is awesome as a rule but tends to soften the details. A little overt edge highlighting helps the print retain the crispness we enjoy on the screen.
Well sure, for print this can help! But i'm looking at a monitor here, so there really is no need to optimize the images for print. (Of course, one can always upload separate images that one wants to sell as a print.)