Everybody wants to be seen owning/using something cool.
I am a classi cuser who runsw without the aero themes, I have a standard background and move windows without any contents. That's not because I don't think its pretty or cool, but because the budget constraints we all operate under mean that I don't have huge amounts of RAM spare, I don't have a CPU that could run a massive compute issue in mere moments, I don't have high speed drives. I am saddled with a standard information worker style laptop and I am squeezing every grunt I can out of it.
Much like most IT departments...
Hell, how many people rushed off an bought iPads just so they could check email and browse the web?

Sure other use cases have come about, but that is the number one use for sure.

So why buy the iPad instead of the myriad of Android devices around? Because of its cool factor.

Now my enterprise IT team has to worry about every Tom Dick and Harry who brings his iPad that he bought from Ebay and how to secure it and connect it up to my services.

Not only that - I ALSO have to worry about how my user is going to handle his devide at home. Is he the exclusive user? What about his partner, his children, his friends?
What about when he is pissed and trying to browse porn while on conference somewhere? How secure is that?

I can take that single user and offer them a cool device, something they would liek, that offers more than just email and browsing and I can secure it out of the box and put corporate apps into a secure "walled garden".

I don't care what he does now (or less anyway) because I have gotten a user to move onto a device that exposes me to less risk. And all that because its cool.
Welcome to the Consumerization of IT. Its a trend.