Well, if they're such a bad design, then what were they designed for, and the design failed?
The design is bad for two reasons (at least!): The first is the form factor - physics is a bitch. The second is the brain deadness of the OS and "Apps". There's no good reason for much of that. Some "apps" are well written, many are not - which is similar to what has happened to computers. Part of THAT is the smartphone-ization of the PC, dumbing down everything to the smartphone level. Much of it is - as I've said before - code grinders who never passed CS-101 - I see software every damn day that has bugs in it that shouldn't exist, and those are often caused by poor programming practices that an CS-101 graduate can tell you aren't a good idea. I have stories.
As for what they're designed for - they're supposed to give the users access to the Internet "while on the go" as the saying goes. The usefulness of that is up for debate, I don't see the point myself. While they do do that, they do it poorly for the reasons cited above. Some of that could be fixed, much of it can not.
