I never really thought of actually taking photos while in video mode. The quality of the photo is not quite as good as being in regular photo mode, but it gives you a much wider frame area. I learned about this while watching a class on Kelby One from Kalebra Kelby.
Here is good article that talks about this photo method as well. How to Take a Picture While Capturing Video on the iPhone
Below are a couple of examples from my short time at an area park the other day. I did edit the look, but not the size or perspectives. The first was taken in regular photo mode and the second was taken in video mode. The title image for this post was also taken in video mode.