I would use this in a security context.

I want to use a one-time pad with a friend. That requires generating a fully random file that I then need to send to my friend (physically). I don't have an Ethernet port on my machine to send the file on the wire, and I don't want to rely on weaker cryptography (WiFI, aes) to send this file (basically, everything is weaker than a one-time pad). I also don't want to leave undeletable traces of my one-time pad on a flash drive.

So what's left is the actual screen of the device, provided I don't have any hidden cameras where I live.

I could use a hard drive and then shred the secrets, but nothing is proven regarding the actual deletion of the files, and QR codes are much cooler!