It's recent. It's a gadget.
The reality is that tablets are more portable. I have a friend who bought one because lugging her laptop around was really proving to be a problem. Beyond that, it's the latest "must have" gadget. It proves that you have more money than sense. Why else would people flock to buy what is, after all, a specialty item that has limited capabilities. If a person is (for example) a student who needs to carry computing power with him or her then a tablet makes sense. For most of us, it would just be another gadget to show off. The only reason I considered getting one is because I would be able to read all of my textbooks in bed, instead of just the ones on my Kindle (a Kindle is a bona fide e-reader, tablets are not). I decided that it wasn't worth the money. I can read my textbooks on my desktop just fine. It won't matter in another semester anyway. I'm graduating.