So the paper images an hominid from the same genus as Lucy. They find that the skull is spongy, like a human skull, which might have a role in bringing blood to the brain. A comparison to another hominid from about the same time, but a different species, shows a solid skull.
There is a possibility this might point to important functional differences between the line that led to us and others. More interestingly, it is showing how new technology applied to old discoveries can increase our knowledge. In this sense, this paper is similar to the work on Ancient DNA.