YC application as an exercise to define and focus your startup goals?

Someone posted a topic earlier for discussion about whether or not to publicize his startup as a "YCombinator Reject."

I've been thinking lately that the act of preparing an application might be a very good exercise to focus and define your goals in a useful way. I don't mean that you should apply if you don't intend to accept if YC accepts you; that wouldn't be very nice. But if you can explain your idea to someone else you're more likely to understand it yourself.

At least part of the reward is in the journey.

no doubt, we have a new team member aboard and are doing the YC app as a team building / focus / vision exercise.

We are going to submit the app, so its a good use of time, but the clarity and focus bits are essential.