It would be nice were that actually the case. However, in practice, I tend to find that doing most things just using voice with my hands on the wheel and eyes on the road ends up being a really frustrating experience. This isn't a particular knock on Siri specifically. I'm pretty sure I'd find Google or Alexa similarly annoying in the same context. As someone says up-thread, Alexa at home is fine for a few formulaic things that I know the incantation for and pretty useless for everything else.