What's the point of Windows RT in a world with low-power X86 processors?
ARM processors yield better battery life which increases the utility of any mobile device. It makes sense that Microsoft would want to take advantage of this benefit with Windows RT.
What I have trouble answering is the following: Now that there are viable options with low-power X86 processors (e.g. Intel's Haswell), why continue with the crippled version of Windows that confuses casual consumers (even more than Modern UI already does)?
With Windows RT Microsoft put themselves in a position where users could only rely on their nascent App Marketplace that opened just eight months ago. At least with Windows 8 proper, there are millions of applications that run in the desktop. This provides a unique half-solution to the App Marketplace, chicken-egg problem with attracting developers. Having a fully functional desktop compensates for the barren app selection. *I know Microsoft announced they just passed 100,000 apps. Given the late start, they're still way behind Apple and Google. I mean, users are still waiting for a proper Facebook app...
Is that extra battery life from an ARM processor worth consumers' confusion when they find out they can't download iTunes (among other programs) on their RT "desktop"? I'm guessing, "no".