Two things occured to me regarding autonomous weapons.

The size of the force would be directly representative of the money invested

That means that war would be directly and only tied to the amount invested by the parties. If you want to win a conflict just spend more money. It doesn’t really cost you anything.

No consideration would need to be given to the human aspects of war, on either side. There’d be no children murdered.

There is a real posibility of deadlock like in Civilization

Given two parties that are equally invested with the most advanced weapons it’s likely that there will be areas of perpetual war. It might not affect people directly but there will be constant investment required in order to not lose the stalemate.

Both of these are especially true if the “soldiers” reach goal-oriented autonomy. Not sure if there’s a word for it, but basically if commands like “capture objective x” can be given. When we reach that point it would become irrelevant and in fact might be considered irresponsible by some to not make use of it.