Who benefits from establishing paternity of a child born out of wedlock? Everyone does. The father benefits because his relationship to his child becomes a legal one. You may think you have a relationship now, but you could easily be shut out of the child's life. Establishing paternity is an important expression of a father's rights.
The mother benefits enormously from paternity. With the relationship established, she is no longer alone. She can turn to the father to help support the child. It is good for her mental and physical health not to have the entire burden of parenting on her shoulders.
But it is the child who benefits most. In addition to financial support, the child gets inheritance rights. He or she gets health information which may prove essential. Paternity allows benefits from Social Security and life insurance policies. It's just good to have two parents and not just one.