I had a great Skype conversation with Remo of White Wall Studios ( Who did the Graffitti QR code http://www.flickr.com/photos/remocamerota/sets/72157623153267947/ ) about how QR is used in Japan, and he brought up an interesting point about usage that differs from the US. He brought up looking and using QR codes later on.
I always assumed that the main UX (user experience) of QR codes was instant connectivity – which I still believe is the main benefit. However, as more readers allow for scanning from your photo gallery, this would mean that users could have multiple QR codes in their Queue. Scan now, enjoy later. Thus, designer barcodes would allow for people to differentiate and remember which code links to what content if they are in a collective place on your mobile.
Thinking of a QR interaction in this additional way could be a great additional selling point.