Removing humans from your side of the war lowers the cost of going to war and allows for even more centralized power. It’s a lot easier to do morally bankrupt acts if you don’t need to convinced a group of human soldiers to do it. Clearly you can anyway a lot of the time, but going for the robots is a lot cheaper/less risky.
It’s pretty obvious why powerful people would want this and why it would be terrible for the rest of us even without worrying about a hypothetical sky net future.