This has been in the game since launch - very surprised to see it still exists when I came back to play around with helis again. Not sure if it was present in Arma1/2 as well.
This gives an edge to anyone who knows this trick, allowing you a fair chunk of extra control authority, making you more maneuverable than those who do not know.
And, since, using the default (current, live) flight model, you run basically no risk of ever stalling your rotors due to low RPM (not to be confused with a retreating blade stall), so it's an all-gain, no risk, situation.