I used the iPhone 6 to make these pictures when I took a walk. It does OK for documentary type photography as long as the focal length is suitable, but some of these have been tweaked in LR in addition to reformatting.
We have two bridges that were moved in the flood, but not washed away, that I still walk across. I took a picture of one of them.
One picture below was made inside the Omni room. I then cropped a section and increased the size to see what is possible in that room. I was standing in the back and that is about the most crop-zooming that I was comfortable doing. The shutter was only 1/30 sec., so any performers would need to not be moving and it would have to be a group composition.
My question of what to photograph is still unanswered and I will not make a decision about using an iPhone until I resolve what and how I am going to photograph in the future.