It would be much better to use LLMs to create ordinary programs than to use an LLM over and over to emulate something that's thousands or millions of times more efficient.
You can't generalize and say that 1 is better than 2, it depends entirely on what you are developing, for whom and for what purpose. For a one-off dumb thing for a few people 1 is fine, for anything at scale, 2 is likely better.
How do you vibe a transformer solution without the existing real solution, which would be needed to generate the training data.
These are just machines for ripping off existing games/programs with mostly accurate simulations. You can't vibe together a transformer of something that doesn't exist with meaningful control over the results.