When the iPad launched, I was in my third year of an industrial design program and we endlessly mocked it. Who was this thing for? It's a giant iPhone. It's not a laptop or a phone, why would anyone want it? Obviously, by the end of my last year we realized we were definitely wrong.
These days I still think we were wrong, but I also think we were more right than we knew at the time.
It's frustrating for professionals, and it's too big for kids to be carrying around, but after observing my parents I realize who it's for: people who have trouble reading on small screens. That's why I like my iPad.