It is actually up to each competition, not even each union, to have a Disciplinary Committee. But those judiciary structures roll up for appeal purposes. So for my location in North America, our union DC rolls up to the USA Rugby DC, which rolls up to Rugby Americas North DC, which rolls up to World Rugby. The same is true for Faz - the RFU rolls up to Six Nations Rugby, which I believe then rolls up to WR.
not a good reason to leave it up. Think about the precedent that sets.