To be honest but all of us just use 50% of all available functions of our camera. So we should create a list with the most important parts of the specification and use it as a basis for decision. I was (and I'm still) confused with a lot of features which I don't know and where I'm still not sure if I need it or if they would improve my pictures. It's some kind of learning by doing by the key factor is time... time for testing and time for comparison to know which settings works best for me.
I got 4k photo function, prety usefull, it take a king of video then, you select the frame you want to keep on photo.
Really usefull for somerhing moving really fast