I do believe much of what they showed was impressive. It actually seems to realize the "personal digital secretary" promise that personal computing devices throughout the decades were sold on.
The most important question to me is how reliable it is. Does it work every time or is there some chance that it horribly misinterprets the content and even embarrasses the user who trusted it.
Yeah, reliability is the crucial bit. Like that example he showed where it checked whether he can make an appointment (by checking driving times), a lot can go wrong there and if the assistant tells you "Yes, you can" but you cannot then I can see lots of people getting angry and not trusting it for anything.
The most important question to me is how reliable it is. Does it work every time or is there some chance that it horribly misinterprets the content and even embarrasses the user who trusted it.