In the first place, it enables the economic agents to insure for a broad range of risks, which is significant to reduce volatility. Moreover, it makes it easier for investors to fine tune their portfolios, which moderates the risk premium required on them and reduces the cost of capital for all agents.
With over 60 member central banks, it has been setting global standards for 90 years now. It is home to a number of significant standing committees which work towards harmonising financial and banking systems.