Anybody ever tried this little gizmo?

Hysteric said

Many reasons for that. Timing and Ignition strength play a big part.

In regards to what happens when you open the throttle rapidly:

The pump shot should never be used to cover over a hole in the fuel curve. The pump shot is necessary to fill the manifold with fuel to compensate for the fuel that condenses on the walls at Zero vacuum. When you snap the throttle open the manifold vac goes to zero basically, and the boiling point of the fuel is increased. The fuel chemicals that were in vapor form at idle vacuum, condensate and fall out of the vapor stream because those chemicals turn to liquid. The end result of all this is less fuel entering the cylinder so the mixture in the cylinder goes lean.

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Yeah, most of us know what accel pumps do & why, & VV carbs tend to scare most folks(even tho' AVS's & even more so TQ's are).
In the NAPCAR case, I believe the physics involved was something along the lines of; ...super-speedways are restrictor plated, that means the intake is functioning at a relatively high depression all the time, keeping normal fuel droplets atomized wasn't/isn't an issue, the 'hyper' atomization actually took up more space & reduced the atmosphere volume in the runners....less air & needless over-atomization cost them power. At least, that's the gist of what I recall about that one particular example.