Do most doctors use powered rasps nowadays for rhinoplasty? What’s the benefit over a manually powered rasp?

No, most surgeons do not use powered rasps.  I have been using powered rasps for over 2 years.  This technology allows me to shave down the bony hump of a nose with great precision and minimal trauma to surrounding tissue.  For more information regarding this technology, see this video: https://www.youtube.com/watch?v=838N2M5MgRw