Well... in most circumstances the GPU will only help graphics related performance. That's only impressive when you wanted better graphics performance, and not general performance. You can't offload anything onto the GPU. Only certain specific types of things, and certain math.
Anyway, this whole article is premature. The benchmarks may not even be iPhone 6, they may be spoofed. They are only one benchmark. Let's wait see what real analysis reveals. Whatever the answer I doubt it will hurt sales.