In a fiat money regime, at the margin, the cost attached to this operation would be close to zero. The benefit, however, would be positive and equal to the value of the new public undertaking multiplied by the opportunity cost of financing the new public function with taxes. The pecuniary value of that benefit to the government issuing money is called seigniorage.
As you know, monetary policy works with long and variable lags, and the Committee believed it appropriate to monitor how its earlier actions were affecting the economy before taking additional steps. As the second half of the year wore on, the data confirmed that a slowdown was under way. But for a while its extent and likely duration were still open questions.