Wait a better video than this for example a Digital foundry video at 4k 60 fps for example and not cut in three where the difference are hard to see. After it is clear, The game has some of it roots in PS4, this is a cross gen title the biggest improvement are on LOD0 character model mostly visible on cutscene. Other improvement out of the good reflection raytracing are more like a higher level PS4 version with improved framerate mode or better draw distance, less popin or better filtering of texture or motion blur, or depth of field, particles effect.
Imo the best looking game is Demon's souls remake.
I hope God of War is not cross gen but I think it will be the cross gen because my impression the best selling title will be cross gen. R&C PS4 and Blooborne sold less than 10 millions. Horizon, Spiderman sold more than 10 million.
Sackboy is probably an exception.