> LLM can do it faster, better, and cost me near nothing.

And this is one the thing I'm skeptical about. The above use case is a symptom of all code and no design. It is a waste of time because you're putting yourself in a corner, architecture wise. Kinda like building on a crooked foundation.

I've never done refactoring where I'm writing a lot of code, it's mostly just copy-paste and rebuilding the connection between modules (functions, classes, files, packages,...). And if the previous connections were well understood and you have a clear plan for the new design, then it's a no-brainer to get there. Same when adapting code, I'm mostly deleting lines and renaming variables (regex is nice).

Maybe I'm misunderstanding things, but unless it's for small scripts or very common project types, I haven't seen the supposed productivity gain compared to traditional tooling.