ok well, have to put it into correct perspective if not people are just being mislead.
I use phone camera as well, and I've some pretty decent shots with them too. I can tell you that phone camera is a good way to train composition but as for exposure wise, it's still very limited. same goes to their White Balance control.
Cameras on the Nokia Lumia / iPhone 4s + 4 + 5 / Note 2 / S3 are great but same can't be said about others.
Mastering your phone's camera is one thing but it's still basically mastering the limitations. It's different from that of an SLR where there are a lot more controls and features.
Believe or not, I had some photos that I used my phone camera to capture instead of relying on my SLR, for example a recent client that wants a pano of their showroom.

End up my Galaxy Nexus pano mode does better than my camera (SLR) photos to be joined in Photoshop CS3. Client still love it though.

I use both. In fact I use phone camera more than my SLR.

The above will definitely look better if I color corrected it.
Can also check out
my Instagram if you dig those photos that underwent filter PP.