We found this whiteboard snapshot floating around the internet:
We found it incredibly funny. We do get clients who want to use a QR code for their event. Sometimes they can be useful ("checking in" to certain elements for an event--like in a scavenger hunt) but mostly it's unnecessary. People generally don't know how to utilize the QR codes, or information could be more easily conveyed in a way that ISN'T a QR code.
Additionally, a lot of people still have to install additional apps/QR readers to process QR codes. This leads to permissions and personal vs. company phone issues.
So our response (with some exceptions) skews toward this flowchart.