It seems pretty obvious (to me, anyway; I'm a home user rather than an IT worker) that in Windows 8, Microsoft wanted to try to appeal to both tablet users with Metro, and to desktop users with the traditional desktop, all in one release. So they bolted a tablet interface to a desktop interface. It's sort of an odd combination, especially if you're new to Metro. Since the OS boots into Metro, it also seems pretty obvious that Microsoft's design choices wouldn't please business users or home users with large, non-touchscreen monitors who aren't interested in their computers looking like a tablet.
As part of its marketing campaign for IE 11, Microsoft's made Windows 8.1 Pro Preview virtual machine images available, so it's easy to try it out for yourself. The Start button takes you back to the Metro start screen, unless you right-click on it, in which case it brings up a context menu allowing you access to some of the more technical aspects of the OS (i.e. control panel; power shell; etc.).
I haven't played with it enough yet to find the setting that allows you to boot straight into the desktop rather than Metro, but even so, it's just one click to go to the desktop. But what they really to make desktop users happy is a Start menu button application launcher, and if you want that, AFAIK, you still have to install a 3rd-party utility.