I disagree about the limitations of uri schemes stated in that article. Having callback url's does not exclude native applications at all (they can just have their own uri scheme to deep link back into). I'm also very sceptical that Scatters web socket server is a good idea. For example you can never keep your keys on your phone to sign for a desktop app and it will never work on iOS because you can't run that server in the background there.

URIs have additional benefits as well. You can print a "Follow me" T-Shirt with a QR code or create a point of sale system that customers can use with RFID.