That's not why Elm is an ideal language for LLMs: it's because, if it compiles, it's most likely working software. Agentic workflows have gotten significantly better over the last year, so LLMs using languages like Elm, Haskell, or even Rust have an amazing feedback loop where even lower quality models can keep trying until things compile.
can keep failing til you're tired of having the agent running in loops, as I said it doesn't matter, agent tools are more effective with models trained with a lot of elm examples