I have a smartphone. The reason I'm never using it to make pictures - even though nominally it has not one, but two cameras - is not its inability to provide fancy DOF effects, it's its overall inability to make a decent picture. My 2 megapixel Panasonic digicam from 2003 (I still have it somewhere... though the batteries are probably long since dead, and there isn't a suitable flash card in the household) was giving better picture quality, differences in the actual lenses notwithstanding. It has its role in my photography however - I'm using it to send the pictures from the field. 
I understand that not all smartphones are this bad, especially not the more modern ones (mine is a 2012/13 model). My wife's Nokia 920 is head and shoulders better, but... at the end of the day it's just that: a tiny sensor with no low-light capabilities to speak of, capped by a tiny fixed focal length lens. Can it make publishable pictures (for online and print media)? Yes, with a few caveats. Does it hold a candle to a basic APS-C DSLR (in this case, the 650D) or CSC (in this case, the Sony NEX-3)? Hell no. Probably not a patch on a µ4/3 CSC either.
I understand that not all smartphones are this bad, especially not the more modern ones (mine is a 2012/13 model). My wife's Nokia 920 is head and shoulders better, but... at the end of the day it's just that: a tiny sensor with no low-light capabilities to speak of, capped by a tiny fixed focal length lens. Can it make publishable pictures (for online and print media)? Yes, with a few caveats. Does it hold a candle to a basic APS-C DSLR (in this case, the 650D) or CSC (in this case, the Sony NEX-3)? Hell no. Probably not a patch on a µ4/3 CSC either.