If I were going to design nano battle bots, I would put this kind of stuff on them. I wouldn't on the defensive nanobots, since they would probably end up getting destroyed anyway in the defense, but for offensive nanobots this would be good since it will probably be hard to develop a lot of nanobots for attacking relative to the number defending, allow fewer offensive 'bots to take on more defensive 'bots before getting destroyed.

Of course, this doesn't mean that a nanowar would be a good thing.