The federal reserve doesn't provide any economic benefit
And the costs of the fed?
Global imperial hegemony comes at a massive cost.
The economic benefits are two fold.
We fund technologies that make our life better like information technologies, medicine, and military resources that help us win wars.
The mandate of the federal reserve is to create jobs and curb inflation.
These jobs allow us to "vote with our dollars" we fund the development of technologies like microchips that have benefitted the lives of billions.
Theoretically people like Bill Gates are supposed to reinvest those dollars he earns in our country not in Africa like he says he plans to. That's how it works most the time.
The cost of war isn't free but our system makes national defense cost a smaller percentage of our GDP than otherwise because our GDP is so large.
The cost of losing wars is even higher. Most of the time historically the loser of the war get massacred or enslaved.
Total warfare was the norm for thousands of years.
They rape your women kill the men and enslave the children. They do this for 1000 years.
We are lucky to live in this era.
So the ability to win wars and have a military that is powerful enough to deter wars ensures we have a future.