in the same way that a clutch plate has springs to take up the shock, the flywheel is in 2 seperate parts almost

it's the same with the front crank pulley being made of a bit of metal and another bit of metal with a rubber in the middle, or the prop doughnut on the seirra

just something else to go wrong because he it fails it makes one hell of a mess and you probably need a new gearbox as well as it tends to smash the shit out of the bellhousing