That is the reason that we use moly disulphide to break the cam in with. I believe you will find that the manufacturers were using syn long ago in certain cars.
What can it hurt? Probably nothing, but, that is not the point....the point is that we continue to promote some things as valid when they are really the untested beliefs of the guy down the road that heard them from some other guy who also believed it.
Also, did not someone earlier justify the belief by saying the engine would use oil? I have not seen a cam make an engine use oil.....