Historiography cannot be a science. It can only be an industry, an art, and a philosophy--an industry by ferreting out the facts, an art by establishing a meaningful order in the chaos of materials, a philosophy by seeking perspective and enlightenment"
From many centuries' history has been projected in a written form. Later, the art of photography took place and now it evolved into motion pictures (both Fiction and Non-Fiction). Just like any other art, Film now is a "new" way of expression which brings diversity of opinions with facts, viewpoints and by converting chaos to order.
People around the world can synthesise information about a country's actions during war. What happened, how and why. Facts in films are very selective due to the expansion of the film's duration, which forces the creators to be selective and show just the key events. This can be good because people can focus on the important stuff. However, this can be very misleading to an uneducated audience.
The whole world can see your perspective on a particular war that included your country or your people. Although this is a good way to put audience in your shoes, it can also turn into propaganda.
Converting Chaos to Order
War is a very complex event that can be very difficult to follow, a film can take those facts and viewpoints and place them in an order that is compelling to watch.
Think about how many war films you've watched and which were the ones that stood out. Were those films about your country? And ask people the same question. The results will speak for themselves.