I think you are making a lot of assumptions on what "practical purposes" even mean in that case.

Please think carefully and then try to tell me whether or not some Trump-administration government agency would not in the "99.99% reliable" circumstance just plug an LLM into the nukes and funnel worldstate input into it and have it make the decision "is it time to fire the nukes?" over and over again each second.

I argue that that would require far more nines than even "will food turn to poison in my mouth" would.