Mundane utility: Void player dentist/doctor/whatever medical field. Okay but painkillers and anesthesiacs are not very good for health, which is downside considering that they are often necessary. But here you have the power of blackout that you can apply to dull the pain. Furthermore, you can decrease ammount of surgeries by voiding kidney stones (scars from surgery can be a pain) and stuff like that.

I like coming up with creative ways to use powers like that.