I've seen a couple of these products and their descriptions are written in a way that makes it seem they are revolutionary and/or doing something mindblowing. But when you actually read into what they actually do, they are just a circuit board that can alter the accelerator electrical input to the ECU (as Kirt had illustrated above).
I first encountered this device being used on a drift car, and I can understand why it might be a useful tool. However, I find it more intriguing to dial down the throttle response rate for situations where wheel spin is highly likely (and unwanted).
I think I might have just repeated everything that Kirt mentioned...
70 to engine rebuild faster than you can say "poofff!"