That's why the article is extrapolating that this would work with an iWatch device that you wear constantly thereby not having to carry your phone everywhere. But you'd have to wear it all the time in the house.
I think what some are missing is that he's saying a grand production of devices won't happen until later in the year. Think gold iPhone 5s. It still launched on target (though, yes, the 'iWatch' has no official target date) although in very limited quantities. The scarcity may be similar for this device. For it to be a part of this amazing pipeline it has to be released at some point.
But it will be more convenient and quicker to do. Instead of 7 arduous steps to send a voice message (open Voice Memos, create memo, save memo, find memo and hit share button, copy or hit text messages, find recipient, hit send) it'll take 3 quick ones (find text message, hold record and speak, hit send).