Originally Posted by
iansmash
I was under the impression that those bars were only for time trials that are short and flat
For true "sprinting," they are kind of lousy, because you want to be able to get better leverage, and you can't hold onto the bars very well in that position. Same reason they suck for climbs (that, and aero isn't as important when climbing).
They could be used for TTs, which are usually about 40K (there are really short ones (and longer ones) as well, but they are less common). Since TTs are not very common, people who are actively participating or training for one are usually pretty good.
They could be used for Tri bikes (probably most common). Competitive distances range from 10-15mi up to over 100mi. Since triathlon has become so common, lots of people are riding around with entry level road bikes with aero bars attached to simulate a "tri bike." However, a newbie's ability to use them effectively is debatable. There is a huge range of riding ability in the tri community.
They are also quite common on touring bikes, because they offer a different position to ride, and let you take the weight off your hands for a little while. Touring is a completely different ballgame, and the speed benefits of the aero bars are not nearly as important.