During the first major conflict of the war, the Battle of Bull Run (7/1861) Washington's elite came to picnic on the sidelines and watch the soldiers fight, expecting the traditional line battle. However, with more deadly weaponry, and especially due to the improvements in artillery, line battles became obsolete, and both the number of killed and wounded increased. In fact, by the war's end, in certain areas soldiers were fighting in bulwarks and trenches rather than standing shoulder to shoulder in the field. During the course of Bull Run, these spectators were overrun as the South drove the North off the field, causing about 5,000 casualties, a staggering amount of loss for a single battle. The breakdown is as follows: Union casualties were 460 killed, 1,124 wounded, and 1,312 missing or captured; Confederate casualties were 387 killed, 1,582 wounded, and 13 missing. People quickly realized they were in for a very long bloody war; historians estimate 600,000 Civil War casualties. One gruesome result of having so many maimed Civil War survivors can be found in the reprint of the Sears-Roebuck catalogue from 1880, which has a large section of prosthetic devices for sale.
Two points come to mind. (1) The design and perfection of rapid fire, repeating, and breach loading weapons did much to facilitate the conquest of the west. With the new weapons, settlers were able to project a disproportionate amount of force to their numbers. (2) The mass production techniques, brought on by the need for large quantities of weapons and goods, were adapted to non-martial uses after the war, enabling exponential growth of industry.
I have a couple interesting twists: Enormous amounts of children were left homeless and living on the streets so some states developed "Industrial Homes or Schools." In Ohio it was the Girls Industrial Home in (Rathbone)Delaware, Ohio, where girls as young as 12 worked long hours under threats of cruel discipline. But remember this was Victorian times where moral zealots professed what was right or wrong. Secondly, the cruelty of the battlefield, showed in its returning veterans physically and mentally and may have caused people to reexamine human worth and compassion. An example would be acknowledgement of post trauma stress disorder(trauma), undefined until 1980 but known during the Civil War as Soldier's Heart.
Also, since there was the rapid fire technology along with more accurate weapon aim, many more soldiers died that would have w/o this technology.