If you were expecting a cloud of artificial smoke to conceal your vehicle from onlookers or nitro boosters to shoot your car up to unfathomable speeds after pressing this button, then you are wrong. What it does do is help your vehicle accelerate without spinning the wheels on slippery surfaces.
In the winter months when roads are covered with ice and snow or whenever tires find it hard to grip the surface on which they are traveling upon, this option applies a brake to the spinning wheel and allows the other wheel, which has traction, to proceed. This is similar to the anti-lock braking system, but in acceleration scenarios only. Special sensors determine if the speed of one tire is rotating faster than the other and apply brake to the proper wheel. Some vehicles reduce engine power to the wheels that are slipping.
Traction Control is a safety option and the only reason I believe the option should be turned off is if your vehicle is stuck it snow. If your vehicle loses engine power to the spinning wheels, that could make it harder to dig your way out. The same goes with braking spinning wheels, as the wheels may be able to dig down to the gravel or whatever is under the snow to gain traction. Check out some great vehicles with Traction Control here.