I generally wanted to be able to trigger events in my house via QR code. Have a very specific use case in my implementation but this flow could easily be modified to trigger lighting events, launch media, or do whatever all without having to log into home assistant. Great way to make automations available to friends and family because all they need is to be on your wifi and have a QR code reader app on their phone.
Watch the YouTube Tutorial/Demo here and hope this is useful!