1 conducts the nation's monetary policy to promote maximum employment, stable prices, and moderate long-term interest rates in the U.S. economy;
2 promotes the stability of the financial system and seeks to minimize and contain systemic risks through active monitoring and engagement in the U.S. and abroad;
3 promotes the safety and soundness of individual financial institutions and monitors their impact on the financial system as a whole;
4 fosters payment and settlement system safety and efficiency through services to the banking industry and the U.S. government that facilitate U.S.-dollar transactions and payments; and
5 promotes consumer protection and community development through consumer-focused supervision and examination, research and analysis of emerging consumer issues and trends, community economic development activities, and the administration of consumer laws and regulations.
Other than #4 (which as you say is clearly is nothing like a think tank), all the rest have significant policy or regulatory actions.
Uh, I agree that the central bank isn't consumer facing - but this is a bit of a stretch. Think tanks don't loan trillions of dollars.