A feature that doesn’t seem to be especially well served by anyone at the moment, as far as I can tell, but I suspect demand for it will grow.
Grabbing stills from video is fine if there isn’t much movement, but if you’re filming at normal video shutter speeds, the stills can easily be motion-blurred.
Even Canon’s flagship R1 can only do it with restrictions: Full HD video, 16:9 stills, and around 18MP JPEGs and with settings matching the video so still vulnerable to motion-blur.
I'm not sure any other brands solve this better yet.