See my Nikon wish list.
I like being able to shoot for a 2 week trip and not have to erase the card, and 256GB will let me do that for still photos. See my Workflow area on how to organize work in the field.
I had purchased a Lexar 128GB XQD card for the Nikon D850 about two weeks ago. It will become my backup card because I just bought the about $350 Sony 256BB XQD card (price went up $50 since I bought mine and the cheapskates do not include a USB XQD card reader).
The Lexar card came with an XQD card reader which I assume and hope will work fine with the Sony card. It’s lame to sell a $350 card without a card reader Sony—this ought to be rectified.