Why the third party dependency repackaging?

Why does the build process for elasticsearch repackage third party APIs (e.g. joda) into elasticsearches namespace? From a user's point of view, should I use the repackaged elasticsearch APIs (e.g. org.elasticsearch.common.joda.time.DateTime or should I just simple use org.joda.time.DateTime). Sorry, I've just never seen a project structured in such a way.