For tens of millions of people, a laptop - or desktop, for that matter - is just a toy. Most people who have a computer at home never use it for productive work aside from, maybe, writing the occasional e-mail. They use the home computer for internet and e-mail, and probably nothing else. The iPad is a good replacement for these people.
The conceit in this thread that people won't use an iPad because it's not useful for productive work - even if it were correct - has no bearing on how most people use their second computer.