Question

Why did Framers give congress the power to issue currency?

Answer 1

The initial idea was that a strong currency could be created at the national level, thereby creating a unique national monetary system.

The US dollar is the official currency of the United States of America. Usually the name used by the currency is usually associated with the legal circulation in that country. After the break of the gold standard in 1971, the currency became, de facto, a fiat currency.

Answer 2

So that there would be  single, and also  a national system of hard money. Thats why :) hope this helps.