The examples are a bit laughable..

"Attach your resume to your business card" - You could just add a web link instead and everyone would understand instead of limiting yourself to a very specific subset of users that know what to do with the barcode. (Same with "attach photos of what you're selling to a flyer")

Plus, is there any type of control on these barcodes? Can I claim a barcode and not allow anyone to add anything else? That would be quite important if you're going to put it on a business card..