Huge advocate of waking up early. I personally find it a lot easier to waste hours of the day at night so avoiding that trap alone is a very big deal.
Your will power and general cognitive performance are at their height early in the day so it does make sense biologically to get up early and optimize your schedule with a nice 4 hour productivity window before you have to really think about anything else.
In any case good story - simple and straight forward reasoning, interesting link, and very easy to follow with takeaway ideas that will stick with perspective readers.
RE: The Best Productivity 'Hack' Out There: The One Thing