You are missing the point of Hybrid SLi in notebooks. It isn't the same concept as SLi in desktops. It is actually a power SAVING feature. Not power wasting feature, like you seem to think it is.
Hybrid SLi, like Hybrid Crossfire, turns off the descrete GPU when it isn't needed. This saves on power, as descrete GPUs take up a huge amount of power compared to integrated GPUs. When the descrete GPU is needed, it is turned back on. Also, in the case of battery powered devices, it can be set to never turn the descrete GPU on when running on battery power alone.
And while we have just started to hear about apps that take advantage of CUDA in the past few months, there is already a very major one coming out that a lot of Mac owners are looking forward to. Photoshop CS4. A large portion of Mac users are artists, artists that use Photoshop on almost a daily basis, so this is a very major thing for them.
