If you really are to chase

or fast overtaking it can be good to have the Traction control switched off.
Thing is when you go on full throttle overtaking ... for example ... as soon as the front wheel lifts ( ... which it would from first or second gear) the engine just cuts down too much and it takes "ages" to get back on power again. Can be a hassle. Though with TC off you have to be a little more careful.
Good thing about DCT is that if you feel the front wheel gona lift ya just switch to next gear in an instant and tame the beast

However, for "normal" driving i usually never switch TC off.