I think it does what most you say, limit the revs after the launch so there is minimal wheelspin. OR I think it realizes when you are holding the clutch and have it sitting in 1st, when you rev it, it wont go past a certain rpm. I think it is the first idea though.
Launch control would have been great on the vette's because my last time at the drag strip, a guy with a spankin new LS3 with the paper dealer tag still on it was there and almost lost to a new tundra(had a 100 shot) because he dumped the clutch so hard he spun and barely moved till he shifted to 2nd by the light tree. Some people need these nannies because they get too excited or something. I would like it to help me get better at launching until I can do it as good as the comp can.