Comment by oxag3n

Legacy code may be very different - I saw legacy libraries implemented in C, with macros APIs that just worked.

Same applies to "live" code with owners still within a team - it can be extremely bad.

The issue with LLMs is you don't know what you get. It can produce a very robust routine, that will just work and have a clear API, or it will look like it, but will have a terrible design decision that will lead to an API redesign.