If it's main intent was to sling oil it would be ribbed or veined to catch oil to sling it. It is not it is smooth. Main purpose is to keep excessive oil that has been thrown off the timing chain and from the oil fog from the crank case for accumulating around the seal area causing a leak. No more oil is needed in this area.
To each their own belief. If you believe you need it use it. Do what you want but if you leave it off don't loose any sleep over it you will not cause a difficulties or damage.