the discs and pads to some extent have to go through a heat/cool cycle so that they don't warp as one part gets hotter than the other and then cools down again rapidly by driving through a puddle

it also stops the pads getting glazed as they can't remove all the heat from the frictional losses they are trying to dissipate

think of it as toast, warming it up nicely means it'll be even all over, but sticking a blow torch on one section will just burn it to a crisp