Re: What are the benefits?
It depends upon your organisation. If you're tracking the development in MS Project, using Visio for diagrams, Sharepoint and MS Word for documents, then it makes as much sense to use Windows for Linux development as it does to use Linux for WIndows-oriented corporate applications.
On the other side, Red Hat have done surprisingly well at making CentOS or Fedora into a good corporate desktop: it can authenticate via AD, do email and calendar with Exchange. So your point remains a good one.
You've also got to consider the Microsoft side of things. Companies have some pride, and not being able to effectively program their own Azure product from their own Windows operating systems clients must have stung.