I find that while tablets, whether they run Android, iOS, or a Windows variant, tend to be able to do most of the things that the majority of computer users do. But they don't excel at all of them.
In my opinion, a tablet is a great device for the consumption of content. Text, pictures, video, webpages, and the like. Where they stumple is the creation of content.
Can you imagine trying to research, take notes, collate data, and then write a term paper or a thesis on a tablet? I can't. This is where my dektop excels, as I can have multiple windows open at once, glancing back and forth, taking notes, and building my document. I'd kill myself trying to do that on a single 9.7 inch screen.