I will say scanners are somewhat unergonomic, but if you had a high enough definition camera, you could photograph the document in its "natural environment". Granted, it's harder to get an evenly lit picture that way, but I think it's a nicer interface.
This is fixed by using anoto paper and a supporting pen!
Fair enough, I actually have been thinking about this topic lately since I have to generate and print and fill out and sign a lot of paper vouchers in my job. I would prefer having a dedicated scanner to just throw them into in a stack with a server/cron job/bash script always watching for new incoming documents rather than a more complex camera setup but yeah something like a camera over your shoulder on your desk could pick up documents too