Stick has the potential advantage of launching at a much higher rpm than an automatic.
Here's one of my ClutchTamer customer's sealed engine Coyote Stock graphs from several years ago, it clearly shows stored inertia energy contributing quite a bit to the car's initial acceleration rate. Energy that was stored prior to the start of the clock, then un-leashed after the start of the clock to boost acceleration. Notice that all the highest points of the Accel "G" trace on the graph occur while the engine's rotating assy is losing rpm (discharging energy) against WOT. But then as soon as the clutch stops pulling the engine down and engine rpm begins to climb, the G trace drops like a rock as engine torque alone is now accelerating the car with no help from discharged inertia...
Just something you might not notice if you are currently "driving into the clutch" like a lot of class racers do.
Grant