Tesla voice commands don't use Siri. In my experience, it's considerably better. You do need to be within cellular range though. I don't bother memorizing commands, just tell it what you want and it will generally work.
The Tesla App on your phone has integrated the ability to use Siri on your phone to control the car. But the native voice commands in a Tesla don't use Siri. To use Siri, your Tesla app must be open and active on your phone. The native voice recognition of a Tesla does not require that. That's why you don't need to say "Hey Siri", you just push the button and talk naturally.
There is a separate shortcut, that is actually preconditioning the truck, I believe its the only way to get precondition a Tesla(Heat batteries etc, not just turn on the climate control.). I created a short cut on my Home Screen that just starts preconditioning. I've also tied that shortcut into my Alarm(iOS can trigger shortcuts when you dismiss an, even add a prompt "Are you going to work").
