This topic has been done before (I believe. I know LFS/real world street driving has been done).
This can go both ways I imagine. If you have never raced before, I imagine there are things in LFS/sim racing that can help you. The understanding of vehicle physics and stuff.
Though, if you already race or run trackdays, or whatever, then nothing beats the real thing. Instead, it would be reversed. The racing or trackday running would help you in LFS.
I don't race or trackday. I take my answers there from experience of the "does LFS help you in real world street driving" topic. I've been driving for 19 years. I do like to get "sporty" with my driving even though I drive stuff like econoboxes and 4x4 trucks. It doesn't matter, I'm a driving enthusiast and know the limits of my vehicles whether they are underpowered ill handling econoboxes, or topheavy slow 4x4's. I learned nothing in LFS that I didn't know out driving my vehicles over the years in a "sporty" fashion. Oversteer, understeer, countersteer, throttle management, threshhold braking, etc I didn't learn in LFS/sim racing. I learned that from real world driving experience.
Thus, if you have no experience, then, yes it will help. If you already have the experience, then you aren't learning anything as you already know.