The burning rubber is to heat the tyre rubber to get the rubber to maximum adhesion, just before doing the run.
> Wheel spinning
Maximum acceleration occurs with some tyre slip - spinning a little but not a lot: https://www.researchgate.net/profile/Masayoshi-Tomizuka/publ... https://www.google.co.nz/search?q=tire+adhesion+versus+slip+...
I am guessing you know that, but just clarifying.
