The problem with mines is the indiscriminate murder. The mines can't be hacked, but they don't know the difference between an enemy soldier in $YEAR and a playing child in $YEAR+10
Edit: 69 was a typo, but I'll keep it.
And yeah, as I wrote my comment I also envisioned self-recharging drones as a logical next step. If you're going fully autonomous, why keep any requirement to come back to base? The one in this story was kamikaze, but if you needed something with more of a punch that became expensive enough to require reusability, then you could have it come home, or just station autonomous ammunition stations at strategic locations.