Doigital MSD 6AL

[rdx]

Has any of you guys used one of these?

http://www.ebay.com/itm/LT1-TPI-LT4-Corvette-Trans-Am-Digital-Ignition-Box-6AL-with-Rev-Limiter-MSD-/130781366907?pt=Motors_Car_Truck_Parts_Accessories &hash=item1e732d4a7b&vxp=mtr

I've seen these devices (Not digital) on some other engines, mainly carburated applications and all I know about them is that they provide a rev limiter so you can have the gas pedal pressed to the bottom and using a switch you then deactivate the rev limiter and let the car rev to the sky or to a 2nd rev limiter (if the device has 2 limiters). Is there any other use for this?