While much of the reason for the scanning ability is based on new near field communication technology -- the ability to scan and buy products -- the iPhone will also have the ability to scan documents, according to PatentlyApple. But unlike most handheld scanners, it's not a procedure that requires a deft and steady hand. From the article:
In contrast, in the foregoing example, the user would be free to move the device freely around on the page in practically any manner, e.g., the device could be rotated, move along an irregular path, moved at different speeds and directions, and the device would be able to compensate for the regular motion and to generate a scanned image as the user "paints" the page with the device.
Apple also plans to let the same iPhone, or potentially any future iOS device, double as a mouse for a desktop or laptop. It also will have "rotational motion data" so it can be used in computer gaming.
It appears that Apple is making the iPhone a bigger part of everyone's life, but the future iPhone scanner would probably most benefit the business sector. I don't think that's a coincidence, especially when Apple has been trying to woo enterprise with the iPad and the Apple iOS.