[r0s]

All that is true of regular type as well to some degree, I guess my point is a standard of readable url type could have all those qualities.

Also the longer a url is out in physical space the more danger of it being replaced online, longevity may not be desirable.

[tpurves]

You are raising all the right points. QR code standards come from an era when cheap digital cameras sensors were MUCH less good than they are now, and similarly when OCR/image-recognition resources were much less cheaply available or built-in to mobile devices.