By studying how the brain reduces noise, we can learn more about how it processes sensory inputs, makes decisions and executes them. Understanding how noise is reduced to very precise commands helps us understand how those commands are created.
This teaches us that these very different neural processes are limited to the same degree by the same noise sources. And it shows that both processes are very good at reducing noise. The differences that exist are likely caused by the separate parts of the brain that are responsible for the separate processes.