They do. 2 paddles in fact. I read the way they do it is.... at the lights,
1) They hold one full in, and the other half way out, spaced by a finger behind it. So because one is all the way in, it takes that one and no clutch is engaged.
2) They rev the engines as they are about to launch (with first gear engaged),
3) Then they release the one all the way in, giving them approx 50% clutch as one is still held half in.
4) Then as they get up speed and gain traction they release the one that is half way in.
And they are away