It reduces the money supply because banks have to buy them as far as I know.
So what,,, they swamped with IOUs and as inflation rises more people taking loans through credit get maxed out and then could default on those loans. But don’t worry the Fed will come to the rescue and buy bonds expanding the money supply to backs creating more inflation. Right now it looks like they want their cake and eat it too but down the road as aforementioned then what.