This is a great question. You can be sure that there will be many opinions out there. In my opinion, most conflict is unnecessary and it causes so much damage. However, not all conflict is futile. There are some cases where conflict is necessary. Here is one cases where conflict is necessary.
There are times when you need to defend yourself, or others, or even your nation in the face of evil. Under these circumstances, you will need conflict, even if it means war. For example, most peole will say that the opposition to Hitler was necessary. The alternative would be unthinkable. Similarly, most people would say that the conflict to abolish slavery was a noble one.