Originally Posted by roadwarrior

Sure...lot's of riders who are in it for fitness have clip on bars...it allows them to rest more of their upper body weight on a bigger contact point which many find comfortable. You hold yourself up a bit less with the abdominal muscles, resting your torso on your forearms.
The deal is that most get their bars, put them on themselves and do not even know that they are adjustable. So they adjust the seat. Adjust the bars for the riding position, do not adjust the riding position for the bars....ultimately, that's my point.
TT bikes have a different geometry. They are designed for aero tuck riding.

Here's some more info...

We are attempting to get the same torso/femur angles by adjusting the bars properly (you can't ride a bike very well by hitting your thighs into your chest). You will not be in as optimal a position aerodynamically (that's why they make TT bikes), but you can be comfortable and able to breathe.