You are right that the further out we look into the Universe, the further back in time we look. And this is a very interesting part of the picture to may astronomers because it allows us to develop models as to the history of the Universe. The current mainstream theory as I understand it is that the Universe is Homogeneous on a very large scale. But if you look at the smaller scale there are clusters of galaxies. What percentage of the mass of the Universe is "dark matter" and how this effects the clustering is still an open question. Also, some have suggested there may be fractal patterns within the Universe. So a good map helps us understand the history of the Universe - it may help to verify some ideas about the Big Bang Theory or perhaps point us in other directions.