I have held a plank IMC rating for many years, and although I have not renewed it in recent times, the odd temporary excursion into the white stuff in a fixed wing did not particularly bother me.
Then a few weeks ago for the first time ever, I experienced inadvertent IMC entry in an R22. What a different world! I immediately exited downwards, but after only a few seconds I decided that this was not a place to be longer than absolutely necessary.