How does YCVC work exactly? YC invests in startups directly already, so why bring in unnecessary partner money? Is it that the YC front runs the investment an

How does YCVC work exactly? YC invests in startups directly already, so why bring in unnecessary partner money? Is it that the YC front runs the investment and the YCVCs are allowed to come on board slightly later at worse terms? If so, that's a good deal for YC, and even if the IRR doesn't work out, the VCs are paying for access to a pool of potential deals. If that's the case VC churn doesn't send the best signal.