I got a new iPhone 5 last week. I'm now using Siri for the first time and that has been an interesting experience. I can see where the ability to talk to a device and have it do something for you will be the future. I'm hoping for the day when I can tell Siri to go to the gym for me, but we are not there yet.
However, I think these devices are at the point where they are more complex than the average person can use or understand. There are now many settings on the iPhones (and android phones) that are buried under layers of menus. Notification settings, network settings, address book complexity, etc. that are sending the management of these devices into a level where tech support will be needed for one's mobile phone.
We recently purchased a new car which has an iPhone interface. The salesman was amazed that my wife had her address book on the iPhone because he doesn't see many people keep that complete of information on their phones. We were able to plug the phone into the car and then select a destination on the Nav system from the address book in the iPhone. Interesting capability but it requires the address book to be completed, an interface between the phone and car, and a car that can use the address in its Nav system. It all worked at the time of the demo. I think we've since forgotten how to do it.
I can see the day, not far off, where we will all have a device that we carry with us that will contain all our personal data, health data, identification, keys, etc. and we'll be able to talk to it. I don't think it will go to the gym for us, but it will be an amazing device.