Fair, I've used it recently to translate a translations.ts file to Spanish.

But for repetitive code, I feel like it is kind of a slow down sometimes. I should have refactored instead.

Similarly I find it very useful for if I've written a tool script and really don't want to write the command line interface for it.

"Here's a well-documented function - write an argparser for it"

...then I fix its rubbish assumptions and mistakes. It's probably not drastically quicker but it doesn't require as much effort from me, meaning I can go harder on the actual function (rather than keeping some effort in reserve to get over the final hump).

I’ve had plenty of success using it to build things like docker compose yamls and the like, but for anything functional, it does often take a few tries to get it right. I never use its raw for anything in production. Only as a leaping off point to structure things.

For the missing 10% : the folder with copies of the code you have already wrote doing that.

(asking GPT-5 to do your dynamic SQL calls is inviting disaster, for example. Requires hours of reworking just to get close.)

Maybe it's the dynamic SQL calls themselves that are inviting disaster?