Both things can be true. It had a genuine purpose, but the fact that Microsoft will go out of its way to not implement anything better and less temperamental is an indication it's not really open. There's plenty of evidence of Microsoft dragging their feet at playing nice with the rest of the office ecosystem.

I'm not saying they shouldn't do that as a company maximizing shareholder value. But we should all collectively groan every time the topic comes up, not applaud them.