I for one would love two CFx cards, just in case. All it takes is one time that you do a photoshoot and come back empty-handed to realize that a cheap SD card is exactly as advertised, a cheap card. You shouldn't expect too much.When the R5 came out it seemed like all the CF cards out there were on the wrong side of that bend. And so when some people complained that Canon didn't put two CF ports on the camera, I was thinking "who are these people to demand Canon set things up so I have to spend huge money on a card I don't need?" Even if it was the same per GB as the newer SD card, you couldn't get less than a quarter of a terabyte no matter what, so they were STILL more expensive than a 64 GB card which was all I needed.
So I'm glad to see lower capacity CF cards coming out...but honestly unless one is taking a zillion pictures or long videos, a 64GB SD card (of the newer, faster type) is likely more than enough. (And even a hypothetical 1TB SD card (again of the newer standard) might be enough for others.)