Design wise maybe, spec wise it’s a big deal for those with an SE, 6, 6S, 7 or 8... That’s a lot of people who don’t want or need a full screen display. No one needs that if they aren’t consuming media if offers no advantage other than worse battery life and more risk of potential expensive repairs, where as the older design is easy to repair, and relatively cheap in comparison outside of AppleCare.
It’s going to potentially be the fastest phone available, period. And future proof for probably the next 5+ years, for not a lot of money for the latest phone tech with a screen many still prefer. Those people being as I mentioned, non media consuming people, older iPhone buyers, younger iPhone buyers etc.