I don't use voice control currently, but I will when the CarPlay update is available because you basically get Siri in your car - you'll be able to say things like "take me home" and the navigation will automatically pull up your home address and start guiding you.
For me, the main benefit of CarPlay aside from Siri is being able to use whatever navigation apps you use on your iPhone, right there in the dashboard, because for me, Lexus navigation is pretty terrible and always has been. I'm curious to see if that also extends to the HUD though, because currently I do like the turn-by-turn directions being displayed there.