the problem is that if I have to nanny it to make sure it doesn’t make a mistake then how is it a useful product?

When was the last time you coded something perfectly? "If I have to nanny you to make sure you don't make a mistake, then how are you a useful employee?" See how that doesn't make sense. There's a reason why good development shops live on the backs of their code reviews and review practices.

The math ain’t matching on this one.

The math is just fine. Code reviews, even audit-level thorough ones, cost far less time than doing the actual coding.

There's also something to be said about the value in being able to tell an LLM to go chew on some code and tests for 10 minutes while I go make a sandwich. I get to make my sandwich, and come back, and there's code there. I still have to review it, point out some mistakes, and then go back and refill my drink.

And there's so much you can customize with personal rules. Don't like its coding style? Write Markdown rules that reflect your own style. Have issues with it tripping over certain bugs? Write rules or memories that remind it to be more aware of those bugs. Are you explaining a complex workflow to it over and over again? Explain it once, and tell it to write the rules file for you.

All of that saves more and more time. The more rules you have for a specific project, the more knowledge it retains on how code for that project, and the more experience you gain in how to communicate to an entity that can understand your ideas. You wouldn't believe how many people can't rubberduck and explain proper concepts to people, much less LLMs.

LLMs are patient. They don't give a shit if you keep demanding more and more tweaks and fixes, or if you have to spend a bit of time trying to explain a concept. Human developers would get tired of your demands after a while, and tell you to fuck off.