Soldato
That was my thought. Anything that can do 331mph can probably spin wheels for a looong time.
My understanding is that (traction aside) there are two main reasons they don't go scorching off the line: firstly, it helps keep the engine temperature and bay temperature down. Secondly, and perhaps more crucially, it keeps the tyre temperature down. Being gentle out of the gate means that everything should otherwise remain happy during the high-speed part of the run. They're using conventional tyres, after all, so they need to do as much as possible to protect them.