I’ll take a nerdy approach at it…
Sounds like a marginal amount of tire slip at launch creates potential energy. When the tires finally grab hard they convert all the car’s stored potential energy into kinetic energy and the car shoots ahead and posts a higher MPH. The cost of the higher MPH is the millisecond or so during the first 60’ it takes to develop all that potential energy. Sort of like a slingshot - if you put it back just a little more it takes you an extra second to do so but the rock flies further and faster.
Conversely, if the tires grab before the cars generates enough potential energy it gets out of the blocks sooner (lower 60’ split) but peaks sooner down the track and doesn’t reach the max MPH at 1/4 mile.