I don't understand why anybody would want to be Satoshi.

He is sitting on a huge stash of Bitcoins, worth (at the time of writing this) billions of dollars, so any casual crack-head who announces to the world to be Satoshi will inevitably be targeted by scammers and extortionists who would try to rob them of pretty much everything they've got. Since most of them certainly don't have millions to sit on themselves.