[ROLF of the HILL COUNTRY]

While you quote the Constitution correctly (accept for punctuation), you err in combining the two sections.
The first, from section 8 of Article I, states a power of Congress. The second, is from section 10, which addressing restrictions on the member STATES, not the Federal Government.
To my knowledge, there has never been a de jure restriction on the Congress from issuing paper currency; they did so during the revolution, and from 1791 up to 1832, when Jackson abolished the United States'Bank.

[DBrow]

I didn’t really combine them, I just searched on “coin” and cut-n-pasted the two sections. Punctuation is as it was on the Cornell site I pilfered the text from.