"This completely eliminates tearing and jitter issues that are common in PC gaming."

Adaptive sync should fix tearing but it won't do much for jitter. That has to be fixed in the game program. Jitter occurs when frames, each representing a point in time, are displayed at different times than the ones they represent. A game program must try to advance the simulation time for each frame an amount that matches the time that will elapse before the frame is displayed, but it can be difficult to know what the simulation and rendering time will be for a frame. Usually that time isn't constant and it can vary a lot when physics, AI, garbage collection, rendering and other per-frame steps can all have unpredictable variations in time.

Still, it's good to have tearing fixed, and to have the option of choosing arbitray frame rates, not just the even divisors of some fixed screen rate.

Hire a contractor. There ain't much call for stomping on chickens.

http://www.youtube.com/watch?v=wbpKV2iMrKk

The I/O limit could be on memory. Servers can have >1000 times more RAM than there is cache on a CPU chip. With enough threads and/or processor cores the cache hit rate drops, so that the memory bus is 100% busy. At that point a faster CPU gives no benefit, may as well us a low-power one.

The camera will also have to be disabled because tap-induced camera motion could be read that way.
It may also be possible to get tap position information from the microphone.

Maybe the person adding the new key didn't pay for the device. It may have been borrowed by police or black hats for spyware installation, or it may have been outright stolen. Requiring secure boot can protect the legitimate owner of the device in these cases if the owner has taken reasonable steps to prevent access without proper authentication.

Another valid reason for preventing unsanctioned OS's to run on the device is to prevent reverse engineering. This enhances (through obscurity) the security of any secondary encryption or authentication that applications on the device may use.

Secure boot is the first step in loading a trustworthy computing environment. Content and media companies will be more willing to license their content for use on secure Win8 machines because they can be sure that the content can't be easily copied.

Content not available on other devices, or only at higher prices / lower quality, is a killer app for Win8. Another one would be widely available and used IP-based voice/video communication, which Win8 will probably have (based on Skype).

Or take things logically in a different direction: Tax the sick. There's no need to theorize about obesity, smoking, age or other possible things that may indirectly influence the cost of medical care.