You guys get more off topic than I can, which I do a lot.
I don't know about non commerce, but for commerce every client alive would love to have cinema quality footage and high end stills they could select.
We've tried it, we've done it but with our older RED's 4k and 5k, they shoot a very different still image than were use to the still photography world.
I would equate it to an older Canon or Nikon . . . much older.
Just like all electronic imaging, if your shooting faces, eyes, etc. (like Mark's reel does to show detail), even 6mp can look good and sharp with a dedicated still camera. It's when you pull back that it gets more difficult with motion cameras.
For one you're normally shooting a medium size to large motion camera horizontal and the frame from uhd to 2 to 1 is very skinny.
This is from an older project and selected only because I like the pose more than the still camera selections.
But it's full length, not that sharp in real life and takes a lot of post.
That doesn't mean the REDs don't shoot a nice file, they have a lot of depth, high bit rate, but even a small shutter angles and/or higher frame rates, the file is never as sharp as a still camera, even at the same shutter speed.*
Now the 8k Helium sensor may solve that, I don't know, but I've been told the main reason for 8k is to kill artifacts in vfx post production.
What I was impressed with on Mark's reel was how well the Helium let bright backlight roll off without clipping. More film like, less digital, because with my RED's shooting into the sun on a backlit subject is very tricky and you have to be precise.
*What's interesting is the little Sony a7sII at 4k shoots a very sharp file from a still grab. They thing about grabbing stills from motion is, 1 out of 3 to 5 is blurred, even at higher frame rates and shutter angle. It's not a camera I'm wild about as I find grading footage difficult, due to low bit rate and 8 bit depth, but it's kind of interesting and when it works it works well.
Today, I don't think there is a less than $40,000 camera you can expect to get quality footage and quality stills. Someday maybe, but we do a lot of parallel productions and essentially shoot it twice.
Though for commerce it really has become a multi media world.
IMO
BC
P.S. In ways the Canon 1dxII is mirror and mirrorless. They're are hard ways to shoot without the mirror and easy ways. If you set it up right just clip on one of those loupes over the lcd and your good to go . . . for motion footage. If you shooting stills, it's still much better to use the optical finder.