Think of the millions of hours of human effort spent on preventing and recovering from the problems caused by completely open computer systems. Think of the lengths that people have gone to in order to acquire skills that are orthogonal to their core interests and their job, just so they can get their job done.
If the iPad and its successor devices free these people to focus on what they do best, it will dramatically change people’s perceptions of computing from something to fear to something to engage enthusiastically with. I find it hard to believe that the loss of background processing isn’t a price worth paying to have a computer that isn’t frightening anymore.
This article by Fraser Speirs sums up my thoughts on the iPad very well. Basically, this is the “computing made simple” holy grail we’ve been waiting for, and most people tech people are too blind to see it.