Quote from TheDudeofLife:
They have historically led to inflation. Especially when the government finances it without rasing taxes.
"War is inflationary. It is always wasteful no matter how just the cause. It is cost without income, destruction financed (more often than not) by credit creation. It is the essence of inflation."
This is very true. It is goods and services w/o a consumer. It consumes manpower, material, usurps the real economy, and causes bouts of intense inflation.
It does, however, speed technology at a breakneck clip. Look at films from 1938 to 1945. It was a world wide depression that evolved into a spending spree. Jet engines, radar, nylon, penicillan - many advances reared their heads years before their time. Too bad 60 million people had to die. WWII also bankrupted Great Britain.
If you could spend your way militarily speaking out of economic collapse, N Korea would be the second leading economy in the World. But you can't.