As a 1 series user I explained in another thread why I am happy with CFExpress and SD combination. I never shoot RAW to both cards but do have occasion to pass off jpegs to social media managers etc. For that use CFExpress is perfect for RAW and video capture, and the SD card perfect to hand over in real time with jpegs to pretty much anybody. SD cards, card readers, and card slots in tablets and notebooks are ubiquitous.
The more I see this darn R3 the more I think Canon have been watching what I am actually doing and making a camera to do that, rather than listen to the childish wishlist I'd spew if I was interviewed by a Canon product management team. The trouble I will have is getting one in stock....
P.S. I keep referring to myself as a 1 series user, I only do this to show relevance, I truly believe this camera is aimed at 1 series holdouts (of which I am one) and can't get over how relevant it is to my specific uses. We have to move away from this idea that all of us should see good in every camera release, what I find appealing and useful others will abhor, that isn't an issue as far as I can see because we have completely different uses.