AMD Hybrid Crossfire: I don't get it

I wanted to check out some competition to NVIDIAs new stable of top of the line chips and came across this article on the ATI Hybrid Crossfire. From what I can gather it is a two chip system that allows a video card plugged into a PCI-express slot and the GPU built into an AMD motherboard act as one more powerful package.

Crysis truly is the “benchmark” of any current 3D video acceleration
technology. With the RV620 video card alone, there simply was not going to be
any Crysis gaming at any reasonable settings, but with Hybrid CrossFire enabled
we were able to actually tweak out a Crysis configuration that would let you
play the game at 1024x768 with most of the visual settings on “Medium.”

It does seem that people with legacy video cards can now play state-of-the-art games on Medium visual settings. That seems like a good idea if you upgraded your motherboard so it works with the technology. I'm still not sure why you just wouldn't spring for a medium of the line video card and just play the game on lower settings without having to upgrade your motherboard. However, this part had me scratching my head:

So a Hybrid CrossFire sub-$500 computer could show up on your Uncle
Bob’s doorstep with Hybrid CrossFire enabled actually allowing him the
ability to play some real 3D games and plug in two monitors without ever
having to switch the Hybrid CrossFire mode on or off.

I'm not sure if Uncle Bob who is buying a sub $500 computer would actually try to play top of the line games on it. If he really wanted to play games you would think he would spring for a $360 Xbox360 or a $249 Wii. Also the 2 monitor-thing doesn't seem like something Uncle Bob would drop another $300 dollars on a new monitor in order to achieve.

I'm not sure what niche this Hybrid Crossfire is supposed to fill. I guess it is there for people who want to use a dirt-cheap graphics card to play games that could probably look a lot better if they just paid a few more bucks for a better card. It makes a junk card go from unplayable on the current games to barely passable for about $500 and a motherboard replacement.