If a cyclist lowers their upper body position to reduce air resistance, they go faster at the same cadence/power. I will leave the arithmetic to others. At 18mph the gain is greater than 15mph. And so on and so forth....
More than 1 way to achieve an equal speed. Efficient flow, more power. Ride efficiently or ride harder. Everyone has the same choice. Physics shows no favorites. At my advanced age, lower beats harder every day. YMMV.
.....and don't forget your readers!
While this position is not an all-day position, if I cannot get to this position comfortably - I consider the bike ill-fitting.