What does that have to do with productivity?

Bugs and security flaws are just oversights. Those oversights are caused by inattention either through fatigue or acting too quickly. An inexperienced person delegating what they don't understand to AI produces more bugs, not less.

Those mindlessly copying from stackoverflow were in a similar situation, but only because they ignored or didn't understand the warnings from the discussion. You're rolling the dice if you expect AI to explain itself, as it can only ever know at most what it scraped from (stackoverflow and poorly documented github repos).

As it was not too long ago, searching on stackoverflow was already a hail mary play. AI just makes the problem worse. At best, with AI there's a lot of reinventing the wheel with no hope of ever doing better than merely approximating the wheel.