i dont think we know everything about the byakudon. I'm sure they have forbidden techniques, i mean sharigan came from hyuuga so what could be the hyuugas secret they are hiding , im sure its better than uchihas, uchiha can copy and see the future but byakudon and see threw anything up to a mile and with it you can cut someones use of chakra off ?? im sure theres more we dont know about it, being they are the oldest clan , im sure theres a reason for it, uchiha is almost dead, only 2 left, lol