How is the word hero defined? Perhaps someone that is viewed as admirable because of difficult choices or difficult things they did. Heroes can come from all walks of life. They can be ordinary or unusual, but they leave an indelible mark. The world changed because they were there.
There is great value and importance in having these heroes set forth for us. Mormon knew that. He knew that people in the latter days would need Captain Moroni as a hero. The war chapters set out the behavior of Captain Moroni and Amalickiah in some detail. Mormon recorded those details so that readers could understand what made Moroni heroic, and Amalickiah despicable.
We need to be more conscious and careful of the heroes that we pick. Some people pick the wrong kind of hero, and that can be a problem. Of course, from the Greeks with the Iliad and the Odyssey is where we get the concept of heroes. Odysseus and Achilles and those figures became models of behavior for better or worse among the Greeks. In our own literature, we have heroes like Joseph Smith and Moroni and others that will serve us even better.
Book of Mormon Central, “Why Did Mormon See Captain Moroni as a Hero? (Alma 48:17),” KnoWhy 155, (July 29, 2016).