You said there would be some benefits from telling them and I was wondering what those benefits might be. Are you still living at home, so you would like to wear diapers more freely? That might be a benefit but I think it might be better to wear discretely on the chance that they might eventually discover a diaper or two. If discovered, you then have a legitimate reason for explaining why you wear diapers. Otherwise, I wouldn't tell as those conversations are usually extremely uncomfortable simply because of the nature of wearing diapers.
On a side note, I thought Mayhem's comment was pretty funny. He does make a point though. How does one just segue into that kind of discussion, especially with parents? Mine discovered my stash and sent me to a psychiatrist so obviously, not all parents accept diaper wearing.