In the old days days of SMS/SCCM it was difficult to determine where to push a package if you had a large enviroment. You had to determine who was in the given area and where/when to push packages to the unprotected and the protected DPs.
What is nice about the Distribution Point Groups is that now you can deploy to Distribution points and if you add a DP to the group it will recive all the packages destined for the group. This wasn't the case in 2007 where it was simply a list and you have to manually select the packages.
Now you can also create a Collection and deploy a content to a Collection as well. When you distribute content, you can target a collection and the distribution points that are members of all distribution point groups with an association to the collection to receive the content.
DP groups: http://technet.microsoft.com/en-us/library/hh427335.aspx
