There's Aperture, Lightroom, Photo Mechanic, Expression Media, and countless other photo editing and photo management programs out there and nothing beats editing, sequencing or pairing images for a portfolio, story or layout than prints.
Perhaps it's the portability. Gather them up like a deck of cards and stick them in your pocket or purse. No need for the extra weight of a laptop or an electrical outlet for power or battery charge. Edit anywhere you want and when the mood strikes.
Perhaps it's more approachable and allows for greater community. It is definitely more challenging to gather around a computer and edit pictures as a group. Prints, whether inkjet or laser, allow people to gather around a table and physically move pictures around. Conversation becomes animated, engaging.
Perhaps because there is no chance of a spinning beach ball of death. You know the ball. There are either too many photos or you are moving way faster than the software can keep up so it hangs and spins... for minutes. Nothing kills a groove faster than a spinning beach ball.
Perhaps because it makes the content separate from the design. There's nothing more tempting than to launch Indesign and dive right into the design and layout of a page or story once the photos become available. Sometimes it works, most often times I hit a wall. Why? It's the layers of selecting the best photos; the best type treatment along with the best pairings and sizes and (!) ... too much.
Stepping away from the computer with prints of the photos allows for connection: to see the photos for content and composition; light and color; moment and emotion. Spread them out on a table and it becomes easier to see the whole and the individual. Then, the pairings of contrasts, similarities, textures or gestures begin, and a layout forms. A story builds.
Perhaps because it's just plain more efficient. For longer multi-page magazine stories or books, shuffling prints or printouts is much easier and less-time consuming than cutting and pasting or dragging photos from one page to the next in any design software.
Go ahead, give your arm, wrist and eyes a much needed break.