Well, that's truth and deeply depends on aims of startups. Sometime, as I see, people try out their Ideas and themselves. As Paul Graham mentioned in following post: "15% of teams change their idea after being accepted."
So, perhaps, if funding is not the case with your startup, I would think about strong media coverage after participating in YC. Which can lead to more customers.
I think YC is not only about funding, but Networking. Funding itself is around 20K$. But value of meeting right people is priceless. So, definitely apply.
- We've already taken some funding. Can we still apply?
- Sure. We've funded many startups that have.
This might be also interesting for you:
- We don't want funding, but will you give us advice?
- Unfortunately we can't. We've invested in so many companies that helping them takes up all our time. But we've collected some general advice in our library.