If you get to the point that things are scanning each other silently and automatically, QR codes are a fine solution. It would be much easier for a hypothetica

If you get to the point that things are scanning each other silently and automatically, QR codes are a fine solution. It would be much easier for a hypothetical 'smart' refrigerator to read a QR code on an item being placed inside than trying to get a clean barcode read from arbitrary angles or visually recognizing every possible object. Similarly, a Google Glasses sort of tech would have a far easier time offering context-aware services if it could passively identify objects by a QR code. No-one would actively scan a poster QR code to order tickets to a movie. But if you were looking at a movie poster with a QR code, you could say "remind me to buy tickets to that" and the glasses would have a much easier time than if they had to visually recognize the particular poster and parse out whether it was for a film or tv show or stage production and figure out where to order said tickets, etc. So... as a shortcut to effective computer vision and understanding that human beings will not ever actively scan them, sure. Why not?