A landmine is indiscriminate, by that logic anything with a triggerable fuze is autonomous (even a snare trap would be). The difference would be if the landmine chose to explode based on some other factor.
Autonomy and intelligence are not the same thing.
Autonomy gets truly dangerous because you dont need to create death zones and no mans land. They are not a less violent version of just bombing the area. They can run considerations and decide by themselves who to kill and with this, their usage outside of active front lines will be considered. And with that, the people deploying them give up the decision and delegate it to an algorithm or worse yet, a trained black box. Reality will be to have completely unaccountable killers bots flying over countries who cant defend themselves against foreign aggression.
This stuff has absolutely horrible potential and i find it prudent to shame and cut out anyone with a sufficient lack of a spine to work in this area. As unpopular as it is to consider the impact of the technology you are developing, it is taught for a reason in a CS degree. This work has the potential to screw over humanity for a while to come.