Well some Parents may find it Useful, however i find that the Ratings system in general Even For movies is Skitso, and even then it only works if the Parents are the ones Who Enforce it, if a 10 year old is playing a M rated game and the parents dont care, then E10+ has the Same Usefulness as wheels on a jet pack, however if the parent is Actually concerned with the content there children are Exposed too, then it Is Useful in given the Parents a guideline to work with.
the Movie Rating system seems to not follow this like games, feels like a form of Censorship and telling the Editer that the movie has to follow There guidelines(in appeals your not allowed to compare your film with others thus robbing you of defense)