[JabavuAdams]

I've read that, but am not convinced. It's very dependent on the particulars of the situation, the goals, the acceptable losses, and the belligerent forces.

A couple of situations:

1) Tyrannical government or Upstart AI wants to destroy dug in and dispersed local militias. Government will use existing military delivery technologies. AI will use non-human elements so blowback is not a concern. It seems here that gas is cheaper than bombs or bullets.

2) Upstart State or AI wants to do a surprise attack to depopulate or logisticall overwhelm a strategic city. Civilian casualties are desired. Again, gas seems like a clear win, here.

The idea that militaries have NBC protection that will just negate chem/bio warfare is a bit of a dream. The operational friction from having to use all that protective gear and protocols would be huge. Even just little things like not being able to aim properly through a rifle scope depending on which gas mask you're wearing. Also don't underestimate the fear/terror/shock factor of being on the receiving end of this horrible stuff.

The future isn't pretty, unless we can figure out a way to settle down and coexist.