This sounds like an insult which I don't quite get, simple old chappie that I am. Please explain.
On topic, it was only when the Mac Mini came along that I acquired a computer. It is easily transportable, but not portable. I am not a geek that wants a computer with me at all times, but I did want something easy to move the guts of, and set up again when I move on. I guess a few others do too.
The other advantage of a modular system is that you can upgrade / update the components as needs or desires dictate. With an iMac in general you have to front funds to replace the lot.