Those are awesome we have a bunch of those in our catalog and more in the magazine. We use them to trigger more information, videos whatever..
I want to do one the side of one of our trucks this year so someone could scan it in traffic.. Then it would trigger there phone to automatically email themselves with the subject line:
"dont forget to get the window cleaned"
Or "dont forget to get the house washed"
Inside the email would be our contact info, etc.. maybe a coupon.