I think that peace is always better than war in every possible way, including economic benefits. But peace comes with lots of costs, and we should not let them take us by surprise. Here is an example.
Ethiopia has, it seems, always been embroiled in civil war. The Tigray War continues, though it is in the news less than at the beginning of the year. It would seem that everyone would want Ethiopian civil wars to end.
Ethiopia has 1.8 million hectares of irrigable farmland, very little of it being currently used. If civil war ended, they could irrigate most of this land. Right now, nobody would invest in Ethiopian infrastructure that might be destroyed by conflict at any moment. Peace would encourage international investment.
But international investment would not be absolutely necessary. The people could build low earth dams (called micro-dams) that would trap a lot of water in small irrigation ponds. If the only war problems were international, these micro-dams would not constitute a military target—too many of them.
Ethiopia is the source of 86 percent of the water that flows through the Nile. Right now, most of that water is claimed and used by Egypt and the Sudans. But if Ethiopians built all the possible micro-dams, they could use 7.2 billion cubic meters of water per year and could store 50. This would vastly reduce the water flow in the Nile. Egypt’s plans to irrigate large new areas would be jeopardized. The Aswan High Dam is a very visible military target, although Ethiopia could probably not endanger it. War, however, might be unavoidable.
This is an example of how peace can cause more war. If you add on top of this the inevitable droughts, which make people and nations feel desperate, you have an ugly situation. And that is in a part of the world we pretty much ignore.
Peace is worth almost any cost, but these costs must not take us by surprise.