Why does Uncle Sam borrow?

Aca "I wish to make a radical suggestion: Public borrowing is an outdated practice, and we could dispense with it entirely. Borrowing by the public treasury and the accumulation of government debt obligations are legacies of the era that preceded the development of modern fiat currency, an era when governments were primarily users of traditional means of payment that lay outside their control, and not the producers and issuers of the primary means of payment."