Why not do those things on your console?
The interface.
Do you think the tiny touchpad on the PS4 controller is best suited to these tasks? The 360 with Kinect may be better, we'll see how accurate its voice tech and gesture recognition is before making final judgement.
But with devices like the 35$ chromecast for dumping media to your TV, and $200 tablets - why would you want to do that stuff from a $400-$500 console?
With a tablet, you have a keyboard when you need it, a responsive touch interface, already a huge selection of apps, the ability to take it with you on the crapper when you're in a Skype call (ok, maybe not) - I don't see
at this point what projecting these apps onto a TV simultaneously with playing a game really gives you.
If you're going to need to interact with any of these apps you're going to need to pause the game, but then you're back in the problem of the input method. Maybe Kinect will make a huge leap forward in dictation accuracy, but it will have to be big to be truly useful for responding to emails/facebook posts/Twitter, etc.
If the input method is not as reliable or efficient as that on a tablet or even smartphone, then the minuscule time saved from having to reach over to your phone/tablet is indeed that - minuscule, and over the course of actually using the app you might have been better off if just grabbing your tablet in the first place.
Well sure, maybe we'll see something truly unique - but that may also require the other party to have a PS4/Xbone on the other end as well, which could limit the usefulness of the app somewhat.
That position is basically impossible to argue though, any real-world example we can draw on could just be swatted down with "Well yeah, but Sony/MS REALLY have something here - can't describe what it is or can't speculate, but just you wait and see!". Based on past history of multifunction TV's in terms of added devices or Smart TV's and their utter failure to propagate that model as anything consumers actually want out of TV - or certainly willing to pay any premium for - I think it's safer to err on the side of skepticism at this point.
Hey, sometimes really large organizations can just plain fuck up. Sometimes they do it often.