What is the purpose of using Lighting in Unity?

The purpose of using lighting in Unity primarily revolves around creating shadows and enhancing the aesthetics of scenes. Effective lighting can dramatically change the mood and atmosphere of a game, making it more immersive and visually appealing. By strategically placing different types of lights, artists can create depth, highlight important objects, and guide players' attention.

Shadows are a crucial aspect of this process, as they provide realism and convey the spatial relationships between objects in the environment. The interplay of light and shadow helps to create a more three-dimensional appearance, which is essential for engaging gameplay and storytelling. Thus, lighting serves not only a functional role but also significantly contributes to the overall artistic vision of the project.

The other options do not align with the primary role of lighting in a Unity project. Lighting is not directly related to improving game performance on low-end devices, defining physics interactions, or managing game audio effects. Each of those aspects correlates with different systems within Unity, showcasing the unique function of lighting in creating visually compelling game experiences.