I LFB on the track when I'm in a fast series of turns where I don't need to shift. The main advantage to me is that I can eliminate the "lurch" from the engine moving in the frame when going on/off throttle. This way I can drive closer to the limit of the tires and not loose it in a load transition.
It also gives you "anti-lag" since I'm (slightly) on the gas even while braking. The downside is it's very hard on your brakes, so you need adequate cooling, and be prepared to change brake pads often.
When road driving there's really no need to LFB (IMO), but I do it anyway to stay in practice
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