At work our video team uses C100s, C300s, and mostly C200s alongside the entire catalog of Cinema lenses. But, even with all their literal hundreds of thousands in cinema gear, they also use the EOS R and the 5D Mark IV religiously. Like gimbal work, mounting cameras in various spaces, handheld work, putting a camera on a 10 foot pole and sticking it in the air, and countless other scenarios where they just generally prefer the DSLR format. And that's even with the somewhat "limited" video specs of the EOS R, which would still be incredibly challenging to spot the difference in a shot between the C200 and the EOS R in any of their published work.
This choice they make isn't because of a lack of experience, and definitely isn't because of a lack of budget, it's time tested additional functionality and we use whatever we need to use to get the shots we want in the way we want. It also seriously helps when you're packing to be mobile and can fit many more of these smaller camera rigs alongside one or two of the bigger ones. I know of plenty of shoots where in a quick set up they've only worked off the DSLRs/MILCs for various reasons or we've quickly swapped cameras between videographers and photographers.
I see absolutely 0 reason these cameras shouldn't be considered for professional video work and have whatever features they possibly can to support that mission.
We're all very excited for the R5, and it's nice that even if the R5 is $4000 we could buy four of them for the cost of one of a single C500 Mark II that the video team is considering, with the benefit of having them available for both my coworkers and I in our photo team and for our video team.