We have used a 2-step on our blown 32-valved BBC Camaro (for burnouts only) because the throttle is very sensitive and we're tired of fixing broken engines. An new driver (old shoe) forgot to push the button and a rod exited the oil pan earlier this year.
But there are other ways to accomplish the same feat like a removable restrictor device on a cable end. We made our own. Otherwise, we prefer to develop the driver's skills.
I'll give you some inside information, the tack on our '57 does not work. Like Andy before him, we tell Eric to drive by feel and instinct.