Even though it is not really great to look at, it was still a big accomplishment for making two identical
Because it's a rather large accomplishment to use steel and concrete. Also, it wasn't originally going to be two towers, they decided to do twins because it would look even uglier with just one.
I don't think the "beauty" of the towers affect how people work in them. Who gives a forget what they look like so long as you can work safely and efficiently.
Studies have shown that office workers who work in a more interesting environment work harder and better. And plus, if you are going to make the tallest buildings in the world, at least make them interesting to look at. "Woo, a giant rectangular prism."
