YAPPADAPPADOO project really nailed it when they used Progressive Web App (App). Even though the technology was currently used by some applications online, they have improved it and they powered it by Blockchain Technology to make it more secure and more reliable.
I'd say yes, there is indeed a great potential for Yappadappadoo hitting the app market big.
As blockchain technology will help them execute purchases, smart contracts and in-app advertisement related payments, the same blockchain technology will keep an app user's blockchain ID keeping your device secure as Yappadappadoo will not store any private information of any app user.
And PWA does offer a lot of advantages compared against the populat native apps, the only issue right now is how to bring the users to Yappadappadoo's PWA from the widely accepted native apps.