We have seen countries start attacking each other on the internet in peace time because it's hard to prove and the costs are abstract. I fear the same will be true for war with robots.
There will be a loss of life in any war. Note that they are called 'Killer' robots. It's just that the loss of life will be of noncombatants.
My concern is not countries waging wars against each other because that can always be deterred, but instead governments using it on its own people. Right now authoritarian governments need to worry about soldiers rebelling but computer code powering the robots isn't gonna rebel when you ask it to kill a city square full of protesters.