For me it's personality, there's a reason we got so many points from losing positions last year (some might also say there's a reason why we were behind in the first place). Raya is better at plucking the ball out of the air on crosses, but I just don't see any other benefit to him under the eye test.
Raya has now made two mistakes in back to back games that have contributed to a goal being conceded. I would like Ramsdale to start against City, doubt it will happen, though.