Name one key benefit of using a deep conditioning treatment.

A deep conditioning treatment is designed primarily to restore moisture to the hair. This is crucial for maintaining healthy hair, as moisture helps to prevent dryness and brittleness, making hair more manageable and less prone to damage. When hair is well-hydrated, it tends to be shinier, softer, and easier to style.

While the other options may appear beneficial for hair, they do not directly address the primary function of deep conditioning treatments. For example, increased volume may result from specific styling techniques or products, but it is not a direct outcome of deep conditioning. Similarly, while certain treatments can contribute to reducing split ends or enhancing the richness of hair color, these benefits are secondary to the fundamental purpose of restoring moisture, which is essential for overall hair health.