You may not give this feature a second thought, but allow me to set a scene for you. Say you're having visitors for the holidays and want to grant them access to your Wi-Fi network. Instead of making the password public (so anyone can use it), you could share the Wi-Fi credentials via QR code. Not only does this approach simplify adding another device to the network, but it also does so with a nod to security.
Sometimes, the best tech features are the ones you don't even actively think about - they're just there when you need 'em, quietly working on your behalf, without any fanfare or intensive effort required. Sometimes, though, those same sorts of scintillating slivers can have the unintended effect of being so seamlessly integrated into an app or process that you completely forget they're there and never get into the habit of actually using 'em. Or, worse yet, maybe you never even notice their arrival at all.