I believe the argument is that not every case needs or desires high fidelity realistic lighting. It is similar effort to take a godot game into a stylized, curated lighting direction, or take to a realistic direction. The trade off to Unreal's approach is significantly more effort to "undo" the realistic lighting and then implement the stylized vision, if that's what the game calls for.

But I do agree, there is value in defaults and it'd be nice to have a "make shit pretty" button that drops in preconfigured hyper real excellence.