Assuming I'm not mistaken and that really is how Handshake is set up (someone please correct me if I'm wrong), then IMO the whole project is essentially dead on arrival. There's no chance they're going to be able to convince millions of large websites to register on a new DNS root overnight. And even if they did somehow managed to convince 80% of websites move to the new system, users _still_ wouldn't switch over because doing so would effectively break 20% of the internet for them.
It's a real shame, because this problem would be trivially avoidable if they simply allowed the existing TLDs use the ICANN roots and confined Handshake domains to their own TLD (.handshake maybe). That way, adoption could happen slowly over time and users could switch over to the Handshake roots with no downsides. As-is though this is simply unworkable.