I think Dave2D commented on it in his review. It seems that it's a non-issue because most 'normal' people won't notice it. Techies and those who appreciate ProMotion will.
My wife literally can't see any difference between her 60Hz iPhone 14 and my 120Hz iPhone 13 Pro. And yet, I can't see anything other than choppy animations and crunchy scrolling when I use hers!