With hybrid SLI enabled it would be able to use the dual 9800 cards in SLI or the integrated 9400M saving power when in 2D applications or on battery. This would help it run much cooler except when playing games when I assume the fans would spool up and only work while plugged in.
I wonder if it's cheaper to include dual 9800M GTS cards over a single 9800M GTX or if they just figure the dual cards would sell more computers. In some situations, especially at lower screen resolutions, the weaker GTS cards in SLI should outperform the single GTX due to the faster clock speeds and SLI. At higher resolutions and shader intensive games I think a single GTX would be superior. I would love to see some comparison benchmarks to verify my speculation but they are so difficult to do it's unlikely we'll ever see such side by side comparisons.
It also seems that the way the article is written is a little ambiguous about the role the three GPUs play in the system except to users who already understand the concept of hybrid SLI and it may lead some consumers to mistakenly believe they can take advantage of the performance of three GPUs simultaneously. Still, it should perform very well.
The links in the article to amazon.com seem to show older models without the SLI.