Hi, AppGyver dev here. I understand the confusion around that claim. Especially taken out of context (
http://www.appgyver.com/supersonic/ui) you can read it as ridiculous hyperbole over something readily achieved with eg MVC architectures. I'll try and explain the difference between SPAs and MPAs and why we think the latter has merit.
A Single Page Application will usually consist of any number of logical views handled in a single web browser view. Since the app is Javascript and HTML, everything is loaded in the same runtime environment and switching between views is actually about swapping things in and out of the DOM. We feel that this isn't a very good approach when you're doing mobile applications, not least because everything you do will be an approximation of the native UI capabilities. Companies like Facebook and LinkedIn have famously failed to deliver hybrid mobile apps with a good enough user experience when using the traditional SPA approach.
This is where an MPA architecture comes in useful. As opposed to a single runtime environment in a single web view, multiple web views can be run concurrently and the native layer is used for transitions between them. This is different from both SPAs and traditional server-side architectures which you could call "multi-page" if you squinted a little. Besides the readily felt advantage in user experience, the approach also has architectural benefits which help out in growing your app. When your Javascript runtime is working towards rendering exactly one kind of view instead of dozens, there are radically fewer possible states and thus less issues with global state leaks and the like. In short, it helps make development simpler.
Hope this clarifies. As a dev, I think the ability to leverage multiple concurrent web views is one of the core advantages of the platform.