Who cares? If they've got the money then fair play to them, why wouldn't you want to have the best available? It's like any other upgrade for anything be it phone, car or kitchen, as long as you're comfortable paying for it then why not?
That said, I let my 3GS contract run out specifically for what we now know to be the 4S, but I'm not getting a new contract just for a minor upgrade to the 4 I managed to acquire a couple of months ago.