The significance is responsiveness — instead of waiting for the LLM to finish generating the entire code block before anything happens, each statement executes as soon as it's complete. So API calls start, UIs render, and errors surface while the LLM is still streaming tokens.

Combined with a slot mechanism, complex UIs build up progressively — a skeleton appears first, then each section fills in as the LLM generates it.

I wrote a deeper dive on how the streaming execution works technically: https://fabian-kuebler.com/posts/streaming-ts-execution/