Long ago, one of my dance professors explained the concept of the personal well of creativity, and how sleep is a key to replenishing it. I thought I understood at the time, I mean, of course you need to get enough sleep in order to dance. Tired dancers get hurt, do not serve the choreographer’s artistic vision, and are not strong.
What she really meant was that the source of your personal artistic stamp on creative work comes from a place that biologically requires rest, but also spiritually requires it. Rest allows the re-ordering of thought processes, the ability to plan and integrate ideas, see various perspectives, make connections, find meaning, and use the tools of your art more skillfully. You reach down into your personal “well” for the tools that make your work your own expression, and you apply them to the project at hand. When you’re tired, it’s harder to reach and there’s less there to grasp.