This way you don't need to design your app to work with different aspect ratios, because it's always the same.

But you still do need to support different aspect ratios if you want your app to work on any other iPhone models, because many of them differ.

Ok? I didn't say this iphone would solve all aspect ratio issues ever. It can only solve the problem for the space it controls, e.g. itself.

that still means it's effectively useless to app developers. who here is creating apps solely for the duo?

Even if it were true you would also have to design the app for when the device is rotated.

Easier to support one more aspect-ratio then two.

Unless these things start selling like hot-cakes (unlikely at the price) a lot of developers just might not bother.