It's OK if you didn't want to, but you can build something cheaper and even more quiet than this new Mac Pro yourself. There are some excellent cases and cooling systems, and you can choose your components with your needs in mind.
With these Mac Pros, I don't think people who buy them are necessarily concerned about specs or cost-effectiveness. I think they are enthusiasts that need Mac OS, and find the Macbook Pro or iMac underpowered.
A person can build something cheaper and more quiet. That is not necessarily the person you are talking to though. Many people don't have that skill set, but say, work in music.
They're premium computers that aren't the highest end specs, but have a pretty good set of specs for the size and noise especially and can be serviced quickly at apple stores across the country pretty easily.
