

I don’t understand how being smart and not needing human input makes these weapons more effective
Probably a lot about humans not usually liking killing other humans. Humans are more likely to accept a surrender or, miss a target due lack of dedication to taking a life or intentionally miss.
Maybe modern professional soldiers. However, there was some research around WW2 with draftees and conscripts that suggested that in the case, a substantial number would not fire on the enemy or intentionally miss in close combat. There has been some debate over accuracy of the results but, the US military found them compelling enough to sink immense resources into attempting to address this through training.
Anecdotally, my grandfather was a volunteer and gunner on a landing craft in the Pacific and would have died, if not for the armor plate in front of him. He admitted to intentionally not shooting at enemy soldiers, when laying down suppressing fire, primarily damaging empty sheds and the like. Despite choosing to be there, he didn’t want to kill anyone.
Compare that to conscripts and draftees fighting in the Russia-Ukraine war and you’re a lot more likely to find people uncommitted to killing other human beings. Most human beings have a strong aversion to homicide, even in war.