The real "money printing" occurs when Congress decides to fund trillions in spending on debt. The Fed flipping a switch to convert that debt into digital dollars is just something their job obligates them to do. Unlike the government, the private sector can't decide to borrow as much as it likes without impunity. With the government swallowing up a large fraction of the liquidity, in a world without QE, interest rates would skyrocket and the private sector would fall into a downward spiral and we would head straight to another Great Depression.