Seems to me a lot of arguing in this thread is coming from people who don't understand how things work in games as far as visuals go.
In-engine cutscenes look better than gameplay because the devs only need to think about where the camera is pointed, so they worry less about making unnecessary things looks good and more about the focal points. Take Tomb Raider for example. In cutscenes, there's swaying grass, and foliage everywhere, and Lara's model has more detail. The lighting is often much better as well. This is because you're looking at a diorama instead of an actual playable stage most of the time.
It's like that Halo 4 video where the guy is showing the scene where Master Chief is standing on the cliff looking at the falling UNSC ship, and it looks amazing, but he turns the camera around and there's nothing there but empty space.
there's a 60 fps version of the video, pal. This was running on a PS4 at 60 fps.
The Uncharted video is doing that very same thing. The only things in the scene are the things we see. Of course gameplay won't be quite that perfect, but that's kind of obvious. This IS in-engine, and if anyone knows how to make an amazing looking scene and apply various tricks to achieve visuals it's ND. These guys managed their own form of Ambient Occlusion and Area lighting in TLoU.