Q:
A: Most models run off of battery and can be easily used on the go. Say you are in a situation when you need to remember something very important, and you have no camera, and you cannot keep the document. You could just pull it out and scan what you need instead of writing multiple pages if information. Plus it saves the trees, less writing you know. ;D And I'm sure it's handy when writing a long essay with two or three rough drafts before the final copy, if it has handwriting recognition.