Being able to just talk is one of the least physically demanding forms of input that can possibly be used and if the language can be understood accurately enough with a wide variety of computer solutions backing the responses, people will become comfortable with asking for those types of responses.

I didn't see anyone say it would be the only interface in the future, just that it would be one of many. Microsoft is saying you can write one application solution and expose a variety of interfaces. Use the keyboard and mouse when you're sitting at the desk with Outlook, or ask Cortana to do that for you if you're across the room or busy driving across town. Whatever is convenient.

"Vaporators? Sir, my first job was programming binary loadlifters—very similar to your vaporators in most respects."