Confidence is one of the most important traits to our evolution. It motivates us to take action in the face of uncertainty.
So the more confident we are, the more motivated we are to face life's challenges and fight for the resources we need to survive and flourish.
The ones without confidence are much less likely to survive because they let life's opportunities pass them by, and thus they missed out on gaining the resources they needed to be successful and happy.
We are living a life full of fear and obstacles, and only confidence can ultimately inspire us to overcome those fears in the face of uncertainty.