I don't scan them too often, because I use WP and my phone doesn't run most of the apps that the codes I see point to.
But when I do scan a code, it usually has the URL displayed before I even get to point the camera properly.
I think the only issue of non-uptake is the fact that we have so many competing systems.
Fortunately, having a wireless CC means that most payments are swift and painless anyway, so I don't really care.
Now, if I could only get my scammy bank to stop charging a fee for *every* foreign transaction, making all but enormous purchases equivalent to theft, I could have used it here outside the UK.