I expect that just like the 5D MK II, studios will be using the camera for scenes where space is limited, and indies on a shoestring may also be using R5's, its cheaper to buy than to rent a high end cinema camera.
I expect that indies will
not be using R5s, due to overheating problems when shooting in 4K and better/cheaper options when shooting in 1080.
EDIT: And if you don't need a full-frame image (and why should you? The most popular cinema camera in the game, the ARRI Alexa, only has a Super 35-sized sensor), you could just as easily shoot 4K or 6K on a Blackmagic URSA or Pocket, each available in EF-mount for $1K to $2K less than an R5.
My point in bringing all this up is just that there are much more capable cinema cameras than the R5 that
don't have overheating problems. If I had an R5, I would use it for BTS/wedding video, but never on a movie production.