Not Quite. In any given gear, engine rpm and road speed are directly related so if for example you're doing 50mph and need to slow to 40mph to negotiate a turn, it doesn't matter which foot you brake with, the engine speed at 40mph will be the same either way. In some turbocharged cars, LFB will allow you to keep the throttle open while braking which may help keep the turbo spooled up thus decreasing any lag the car might otherwise have. The main goal of LFB is smoothly transferring weight around the chassis while braking or accellerating.