I mean, isn't that a great example? Yes, they both can play/run the same games, but framerate and resolution differences are pretty apparent between the two systems. Yes, there are some titles that run "better" on PS4 Pro but those are few and are all titles that were specifically sponsored by SONY. Destiny 2 for example comes to mind when thinking of the differences. Resolution and framerate is very clear.
I should say I'll be getting both systems and have both this gen as well. So no fanning on my side. I just know right now, I play majority on XBX simply because it's giving me the better visual experience. i.e. Division 2.