On my A7S2, I use 1, and 2 on the custom camera dial to program my video settings. So I have 4K on "M", 60P on 1 and 120p on 2. I can just switch flick the dial and shoot video real fast.
On the A7R3, you cannot get Continuous AutoFocus unless you're in "Movie" mode. Since CAF with that camera is so good, you can't use the dial to program in video shooting profiles (unless you're willing to pull focus manually). In movie mode, I'm constantly having to reprogram the camera.
Is the above because the A7R3 is primarily a stills camera and the A7S2 primarily a video camera?