Noise Cancellation
Using the microphone we should be able to do some noise cancellation. Maybe when playing music the Neo could record the ambient noise and try cancelling that.
When listening to music using ear-plugs/headphones with the phone placed in your pocket, the phone's microphone will probably not record the exact same noise (additional scratching sounds?) as the noise you hear interfering with your music. Still, just some correlation between noise signals may prove enough to provide a partial noise cancellation improving listening experience.
Also, depending on hardware constraints, noise cancelling could be handy for phone call conversations in noisy environments.