Is it really so hard to imagine the use case for the +Steam
Machine? Sign me up as one that doesn't want to deal with a windows machine. I have a mac and the idea of dual-booting is not appealing. I don't want to deal with all the windows updates, viruses (and yeah, know OSX gets them too, but they are still more common on Windows) on two operating systems.
When I switched to mac, I went to consoles for gaming, but the truth is I like 'pc' gaming a lot. I can play a lot of steam games on OSX, but there are many that still only work in windows.
I realize that the steam machine won't get more games than OSX (probably) but it's still more appealing than dealing with a windows PC.
Justin mentions that a windows machine can be used for spreadsheets and word processing, but I already have that elsewhere.
Having said all that, I probably won't be getting a steam machine unless there is a game on that platform I can't get on my PS4 or OSX.