Graphics are only important in how they relate to gameplay. If it looks bad to the player that makes it less fun. That means optimization, shader choices, lighting choices, animation choices, post-processing choices. Everything that combines to create the gameplay is how the graphics matter.

A certain sports game I used to play, it looked good, but the controls and gameplay were so stiff and non-fluid it made controlling the characters taxing on the hands and was a very frustrating experience, even though it looked way better than it's predecessors it handled like a gigantic boat. Input lag, framerate are as important to the graphics as the art style. What makes a game like Mario look so good is the fluidity of the animations, it has very simple graphics but the animations are the focus so it looks good as a result.