To say that any phone could be a subsitute for an APSC, F2 monster like the X100S or T would be ludicrous. As would be to claim that I never leave my big cameras behind knowing that my phone is often enough.
Both iPhone 6 models feature the same 8-megapixel camera with phase-detect autofocus and ƒ/2.2 lens. The iPhone 6+ adds optical image stabilization.
It's a gigantic phone. But it's also a paper-thin camera with a gigantic rear LCD.
I'm going big. I mean, small.