Why iPad

There have been a million threads on this question, but in short: more portable than a laptop (you won't realize just how true this is til you've got it), bigger screen is more useful than a smart phone, better for reading stuff than either.

But some people don't need that, and a laptop + smartphone is plenty for them.

 

If you have a laptop and a desktop you do not "need" an iPad.

You get an iPad because you "want" one.

 

If someone has a desktop and no laptop the need/want for an iPad would be greater than for someone with a smallish laptop that could help fill the void

 

http://www.apple.com/ipad/

Long battery life. Multi-touch. Etc.

 

- portability
- long battery life
- hand writing features/ can annotate with a stylus

I can't do any meaningful work on my smart phone due to its size, but I do quite a lot of work related stuff on my iPad.

 

The only way you'll know if its for you is if you try one out. Go to the Apple Store and play with one?

Personally i've always found it more convenient than a laptop to carry around the house.

 

Subjective matter ("the point" always is, regardless of topic). I have all three and find all three useful. YMMV. Consult the countless existing threads on the matter. I also recommend trying one out. You can't beat first hand experience for assessing such things.