When you are accepted at YC you are already a team which is autonomous and capable. With or without Bookface information things will not change much. Maybe you

When you are accepted at YC you are already a team which is autonomous and capable. With or without Bookface information things will not change much. Maybe you can save an afternoon because the information is easier to access and already curated. But nothing life changing for sure. What really is important is connection to other people, when you are starting a B2B saas companies for example the people you are talking with on BookFace, are all potential customers, and can make your first customers easier to find.