Hey guys, I just made two res comparisons using Infamous: First Light and Rise of the Tomb Raider on the PS4 Pro. This will give you guys an idea of what this res bump can really provide in terms of clarity. Especially so since both of these games already render at 1080p on a regular Pro. Also, both of these games utilize checkerboard rendering with one of them, Infamous, only checkerboarding up to 1800p.
Tomb Raider:
4Kc
1080p
Infamous:
1800c
1080p
So as you can see, the benefits of the res bump from an already crisp 1080p are pretty noticeable. These two games, again, aren't even naively hitting the higher resolutions either.