The following was posted on the MyNintendo settings page.
“Present this QR Code® to check in at select Nintendo events and locations. Checking in gives you access to exclusive My Nintendo member benefits that may be available. Benefits will vary, so stay tuned for more details.”
It seems that with the Switch coming soon, Nintendo is starting to revamp MyNintendo and finally make it a true account and reward system. Hopefully it will become better than what it currently is.