Oh please the neural engine is mostly useless for LLMs. Siri in iOS 27 is laughably pathetic and slow compared to GPT Live DESPITE sending personal context to their (attested) cloud to execute anything but the most basic queries. Still years behind.
That said, Siri seems a little bit better now - my subjective opinion. It is a little bit less frustrating.
And the voice is still a poor text to speech model, very far behind GPT live.