Very small portion of people have multiple monitors and the vast majority of those that do, do so for productivity, not gaming. Dissapointed ATi have to churn out this gimmick to get people saying "OMGWTFBBQ, that's cool but I can't afford it or won't actually have it". Multi-monitor setup like that is nothing new or exciting. One good thing though is that it encourages manufacturers to create thinner and thinner bezels, cos let's face it, they are horrible, especially in situations like this.
Multi Monitors are nothing new, but actually in a properly usable format like that they are currently exceedingly limited, you basically have the option of Matrox TripleHead2Go (which is ~£150, and only supports 3x 1680x1050) or SoftTH which is software that requires tweaking and also has a substantial performance hit over the hardware version.
Eyefinity gives the flexibility of SoftTH but with no performance drop, and that is a big chunk better than anything else available.
I think you'll also find that the majority of sim gamers (Racing and Flight especially) either would love to have multi-monitor, and in the case of quite a few already run it with either of the two options above, and are looking forward to doing it all within the graphics card.
It'll also benefit quite a few other games as well, although some (like FPS, and Racing sims for that matter) wouldn't really suit a 3x2 setup like they show, but 3x1 or even 5x1 would be awesome...
Of course 3x3 would be best for an FPS
