Make returns easy with out printing
I don't have a printer, as I'm sure many people do not. The new way of showing the label on your phone at the post office is easier, however, if a return barcode sticker was in the bag, which you'd activate by scanning a corresponding QR code, then apply- one could simply post the package back without going to the Post Office or seeking out a printer.
Julie conquest commented
Excellent idea above. Put a return address sticker with barcode in the bag for us so we can drop it into any post box without going to post office.