Very little I'm afraid. It sets the car off in 2nd rather than 1st, to use a manual analogy. I'm sure it's more technical than that, but it is intended to help stop rear wheel spin. Nowt to do with the traction control.
Unfortunately a combination of auto and real wheel drive equals useless snow and ice control, unless you do the really sensible thing and put on winter tyres.
What with all that trickery on board too..
Last winter I was pushing my friends M Sport in the snow as Golfs were driving by wondering what the fuss was all about - I took the rise then and guess he may get his own back then!!