FIVR is the most obvious main use for this I've been following this stuff since the 00s, "The Singularity is Near" is basically my bible. Back in my audiophile days I used to dream about something like this for music, so it's interesting to see him mention that use. With this you'll finally be able to actually perceive the extra frequencies and achieve sound quality impossible on speakers.
With A.I. you could analyze a song and give each instrument and sound the proper presence and location.
Live drums will sound and feel like the real thing Bass will have so much more depth Synth textures and noise will swirl around you sounding like they're in actual physical 3D space
This is going to be super exciting for music but will be totally lost on normies and black people.
In the near future this could be a way to produce accurate and realistic sound for HMD based VR. Still, getting a brain implant for something like audio would be very drastic and will likely stay a niche thing.
BCI implants will only ever become mainstream when full-immersion virtual reality is possible.