An interesting point to bring up, is the destructive capabilities of the APC's Independently Targeting Particle Beam Phalanx, something that could independently shoot, probably invisible, kinetic accelerated particles that f**k up anything in its path moleculaly, let's say you have multiple APC's.
Whoever is in front of an APC would be doomed, and if we're not talking orbital bombardment of strategic locations that would send reinforcements to a ground engagement. I think, in terms of human on human combat, it doesn't matter how cumbersome the smart gun is, based on how often costs are cut in this world, I'm assuming that's the case with the smart gun, but cut because feet on the ground would probably come in to clean up what ever the hell that was left after a "Fry half a city with this puppy"