Is it me, or is the benefit of that extremely small? I can move my finger and tap the 'Instagram' icon quicker than I can say "Instagram". Never mind that the app itself is highly visual, so there's no point launching it without already looking at the screen and holding the phone to your hand.
When I’m inputting my home address in a web browser (on mobile or desktop), I should be able to tap the “State” dropdown and just say “California” and it have it select that option for me.
Or it should just already know your home address. That's why I don't think Google Now should be included in this criticism - the idea of it is to preempt any need for you to issue voice commands, because it's already presented you with the information you need.
On iOS, when I get a notification that covers the top of the screen, I should be able to just say “ignore” and have the notification instantly disappear.
I really don't think voice is a great interface at all, because it involves invading other people's personal space. I don't want to be sat on the train with people saying "Instagram","Facebook", "ignore", "ignore" all around me. I don't see what's so bad about the current interfaces, nor do I see anything in this post that is particularly new or insightful.