One of the biggest obstacles in writing is overwhelm:"I don't know what to say. I don't know how to say it. There are too many choices. It's overwhelming."
One of the most reliable ways to defeat overwhelm is to get the voice.
If you don't have the right voice for a piece, writing is a struggle; if you unlock the voice, it's an order of magnitude easier.
Because "voice" represents an entire complex of choices about vocabulary, syntax, pacing, and perspective. By collapsing the range of possibilities, voice makes the writing more accessible and less overwhelming.