Originally Posted by smashndash

Having lower bars allows you to ride in a lower position with straighter arms, something that works better for going fast over long distances. It allows you to have straighter arms while descending - this reduces stress on your elbows. It allows you to sprint in a more aerodynamic position.

So essentially - a lower bar position facilitates a low torso angle better than a higher bar position. What you need to ask is “how often am I riding with a low torso?”. If you are frequently bending your elbows like crazy or climbing in the drops, chances are that you’d be more comfortable with a lower bar position.

If your question is “why should I ride with a lower torso angle?”, there are 3 reasons. First one, obviously, is aerodynamics. Lower torso angle usually means you’re catching less wind. The second reason is cornering. The flatter your back is, the more weight on the front wheel, and the less risk you face of your front wheel washing out in a corner. The last reason is counterweight. The more you lean forward and take weight off your butt, the more weight you can theoretically put on the pedals. This helps push down on the pedals.