I'm sure Apple has taken into consideration the value of each button, programmed or not, whether on top or the side, of their "Mighty Mouse," before releasing it. I do, however, think it's interesting that after only one click from Mnelsons' girlfriend, that she had difficulty getting it to work again. That's certainly not a piece of hardware I'd want to invest in. But, I can't imagine Apple sitting on it's laurels for too long if there are questions of the Mighty Mouse's quality, since quality is something they highly promote.
Besides looks, Apple has always promoted it's simplicity in operation as compared to the complexity/diversity of the operation of PC's. Thus, I can understand their direction in advertising this new mouse. It certainly attracts a larger audience.
So, does it boil down to money? Ultimately...YES!!