Wait, what exactly is happening and how is it significant?
GFWL was basically "Steam" that was designed and maintained by Microsoft and used the same Gamertag system that Xbox LIVE uses. the problem however was that GFWL was slow, unreliable, and prone to problems a lot of the time. GFWL acted not only as a DRM but also as the online backbone, i.e. automatching, server lists, etc. once Steam came with Steamworks, their own online backbone which as much faster, reliable, and less problematic, GFWL basically bit the dust and one by one game developers started dropping GFWL in favor of Steamworks.
i for one am incredibly happy to hear this. GFWL was slow and awful to use, i don't care if some of my games won't have online anymore.