Because people are already trying to use bitcoin in shops. In the german section of the forum, there is a post about a restaurant in Berlin, where one can pay the bill with bitcoins. The biggest problem seems to how to enter the address. Saying and typing the adress is way too cumbersome. What they did first, was to send an email with the address. But using the cellphone to get the address by decoding a QR-code is the common opinion on how one should do that. In the sense of the workflow, copying to clipboard or generating a QR-code is the same thing.