Bottom line ..
if you are truck driver or a mail man ..probably smart phones (with smaller form factor) are good for you...
If you are are a creative....... eg code , write , read , plan , notes etc .. and you are anyway in front of a terminal most of your day ... smart phone is a wastage of money, time and productivity..
Always have a good GPS in your car .. cuz networks and flimsy iPhone are anyway not dependable for navigation ..
Always have a good camera ( SLR or a goPro) when you go out in nature.. don't waste your time and creativity with shitty phone cams ..