I had this question too , my "WHY" is cost ! In my country we have to buy OSX Server software separately so it would add +/-$1000 to the cost of the mac pro. Noise and heat not an issue ; Mount the server on the other side of a brick wall and drill hole for cables etc. Would like the server software but would prefer a mac pro
You can, but I don't see the point. First of all they are bloody loud, even when they are idling. They are designed to be mounted in 1U cabinets, so it will be hard to integrate into your workspace (I'm guessing). To name a couple of problems.
I would go for a Mac Pro, they are much better desktops.
They - and more than some other rackmount servers, regardless of the rated operating temperature - are designed to be used in a controlled environment. By using them in varying ambients beyond the mid-20C's at most, you may end up with a shorter system life than even a glorified home computer like the Mac Pro.