The iPhone has a great tool for street photography. Not quite as good as the Ricoh GR 3, but good enough.
My only critique of the iPhone for street photography
The other day when I was shooting Street photography in downtown LA, I shot some photos with iPhone Pro, and some photos my Ricoh GR three. I still prefer the Ricoh GR 3 photos at least 20 times more than the iPhone photos. But if the iPhone is your only tool, it is good enough for street photography.