Ah the joy of watching an end user use your application. Glad to see MS still does it. It's one of my favorite parts of building applications.
It isn't just about knowledge transfer from the "guru" to the "learner" - it works the other way too. I got an idea for a new feature in one product after watching my wife, Trish, simply try out a product. All of the assumptions and "learned" behavior go right out the window and instead, you're left with thinking "how can I make this process easier?" while still "how do I ensure the user is learning?".