It destroyed the 'price discovery' mechanism of warfare.
It used to be that if a country had beef they'd go fight it out. Now we gotta figure our weird networks of proxy wars and anything to avoid directly fighting.
The further violence gets from those parties in direct disagreement, the more damage is done and the less is resolved. And the push from tribes to kingdoms to city states to nation states to UN has all been one of cowardice -- of finding ways to get others to fight on your behalf.
What once may have been resolved by some fists and pints now has to be calculated to avoid killing all life on Earth.