Senran Kagura: Estival Versus?
Hadn't even heard of it before, but yeah, that's a stylistic game.
The point I really wanted to head at is that just because something 
looks simple, doesn't say anything about what's going on behind the scenes. Rendering is an extremely complex process that must take in large assets and perform a lot of heavy 3D Math to decide where objects exists and what needs to be displayed, how those objects are going to be coloured, how those objects are going to be lit and shadowed, if there's any additional special effects for objects (such as using Normal Maps to extrude the surface of the object according to the way the light bends around the object), and once the final rendered pixel map is generated, there's another series of processing effects before it is shipped off to the monitor.
Stylistic games generally tend to forgo complex lighting to use the same (and/or additional) performance to do other kinds of effects, such as the EXPENSIVE process of cell-shading (this is why Borderlands uses a fake cell-shading process where the artists manually paint the black lines onto the character textures) or more complex forms of blur. These things tend to be more subtle but would be extremely noticeable if they weren't there.
I know based on my studies that old-school Ratchet & Clank was upscaled, because even at a reduced FPS it could barely stay in frame limits because of just how expensive the render process was, and that game has barely any lighting (which was all faked); the PS4 version is 
not much better. The benefit is that R&C was made up of smaller levels with less in memory and more faces to cull out wide backgrounds. LoZ:BotW doesn't have the same benefit and needs to rely on much bigger worlds in view at all times.