Is this doing the same thing as https://gitorious.org/gitorious/ ?
They hosted their code on github, doesn't make much sense to do that IMHO.
If the answer were the former, I'd have to say that many a team use Git internally without being able to host it on a third party service and would benefit from a simple UI to make things easier. If the answer was the later, I'd have to say that any code you intend to share with the community should be hosted on Github and Github only.
Or I could just be wrong, that their goal could simply as if they don't want people to share code with GitLab.