When the light is on, that means traction control is OFF.
I always leave traction control on (light being off) until I want to drift or delibritely break my ass end loose, then I turn it off for the drift or whatever, and put it back on after I'm done and re-situated
You will not gain any power or acceleration times if traction control is off, if anything, it will help launches because when the wheels spin, you have little to no pushing force against the pavement, so your car can't accelerate as fast. It also has the wonderful side effect of keeping your tail from spinning too much in the snow or slick pavement.
If you get stuck, just turn it off and get out the good ol' way.