Aside from further justifying the upcoming fall Xbox 360 dashboard update, the integration of Xbox Live into Windows 8 means more to Microsoft than it does to us end users. By working hooks for the service directly into the next generation PC operating system, MS will no longer have to worry about getting gamers to download Games for Windows Live, a service that never really caught on in the first place.
Xbox Live's Major Nelson says that developers are being shown tools that make it easier to integrate Xbox Live features into PC games during the show, which I'd imagine are the same tools used for Games for Windows Live, only rebranded.
Perhaps I'm being too skeptical. The Major says they there are many more details to share about what Xbox Live on Windows will be capable of. Let's remain hopeful until then. That way we'll have more energy for giggling and pointing.