Actually, two Windows here mean the two different worlds in Windows 8, one is designed especially for touchscreen devices and another for a computer with mouse and keyboard. But, unfortunately it isn't possible to install/use those individually/separately.
So, If we can't use these two worlds separately, What's the benefit and why they both are superimposed into a single Windows 8 operating system? The reason that gives me an answer to “Why” probably is that:
PC sales growth was going down and the tablet/touch screen devices were on high rise, So here, Microsoft want the same operating system to be used in both the regular computers and tablets/touchscreen devices without compromising with the 600 Million regular mouse driven PC's which were already in use. And, thats the benefit too, Now there is no need to have separate operating systems for different type of devices.
Personally, when I use Windows 8, it gives me an experience of using two different operating systems at the same time but still I love that, because I love to explore different operating systems regardless of what the consumers says about it.
So, here I just want to know whether you too feel the same? Or just I'm mad!