What I mean is, for some wars like WW2 or WW1 it could be argued that the boom in wartime technology development or economic development (from weapon sales etc) ended up creating advantages for the US in the long run. In the civil war however, the US sustained all the damage from the war, suffered all the casualties, and had to deal with what seems to have been a very contentious period of reconstruction for the south. Slavery was abolished of course, but were there any other not-as-obvious benefits to the civil war?
The end of the Civil War was a very significant, if not the most, event in US history. The conclusion of the war can essentially be boiled down to a few main points:
Now, all these points all factored in, what the United States gained from the Civil War in the long run, called the Second Industrial Revolution. Post Civil War, the US underwent a rapid and economic revolution. The country enjoyed abundant natural resources, a growing supply of labor, an expanding market for manufactured goods and the availability of capital for investment. In addition, the federal government actively promoted industrial and agricultural development. It enacted high tariffs that protected American industry from foreign competition, granted land to railroad companies to encourage construction and used the army to remove Indians from western lands desired by farmers and mining companies. There was a transition from being a farmland nation, to being an industrial nation. People moved to the cities.
Sources:
Foner, Eric. "Chapter 14. "A New Birth of Freedom: The Civil War, 1861-1865" and Chapter 15. "What Is Freedom?": Reconstruction, 1865-1877." Give Me Liberty!: An American History. Seagull 4th ed. Vol. Fourth. W. W. Norton, 2014. 509-592.
Notes from my bachelor on American Studies.