Ah, I think that may be due to the patch submission structure of Phabricator more than anything else. I can understand why a major open source org wants to adopt something else that people have as muscle memory (ie. pull request style collaborating). I don't think that reflects the development of Phabricator at all, like I said, its become more robust and features are becoming more mature every week (and there's still some big installations out there, like Wikimedia).