Yes, knowledge about the past is useful to complete our knowledge of the world we live in, because if we do not appreciate history, it is bound to repeat itself. Humans are the same over time, and appreciating what the ones who have done before learned will help us not repeat mistakes and understand where society is at.
The world that we live in did not arise out of a vacuum. It is a culmination of the errors and achievements of the past. By studying the past, we can understand what society and humanity can do in order to strive for a better world. We can also avoid the pitfalls that impacted negatively on human growth and knowledge.