The patent also mentions allowing third-party apps to make use of voice commands, and that users could be audibly notified of what app they had selected along with a list of corresponding voice commands. This could come in really handy when driving the car or riding a bicycle, when one's eyes should be on the road and not staring at an iPhone screen.
Now I don't know about you, but I have never been able to reliably use the voice command feature on my iPhone. The few times I've tried to use it, I ended up calling an ex-girlfriend when I meant to call the current one, or I called my grandmother instead of my brother. So any improvements Apple could make to voice command would be more than welcome. I have used other voice command apps like Dragon Dictation and Apple's recent acquisition Siri, but a context-based voice command system would be a great addition to the iPhone's abilities.