So how does Apple use those dual cameras?
At least on my Honor 8 the benefits are really obviously. Dynamic range is great and it clearly lets in more light. It's not possible to take pure bw shots since no Leica branding but still. Sharpness is great from center to corners but the dual camera thing has hardly anything to do with that.
There's that fake dof thing too but fake is fake and never as good as the real thing.
The zoom was the first thing to show up and, from what I've seen, is implemented pretty elegantly: you can either tap a button for a quick 2X zoom or use a scrolling zoom that automatically switches to the longer-ranged camera at a certain point. As close as you get to optical zoom without a motorized lens.
The other bit is the "fake DOF thing," as you put it. Yeah, it won't be as good as the real thing, but there should be many times when it'll be close enough. I'm particularly interested to know how that works in practice.