Better data transfer speeds. It'll reduce the time inbetween taking pictures (as it has to save the file to the card and then return back to picture mode), and it also helps with if you have a camera that has a multi-shot function, that takes stills in series. E.g., you see 3 photos of a person swinging a bat. One as he's swinging, one midswing, and another at full-stretch. That was most likely done with a multi-shot camera.