Adding demand and thereby liquidity to a market creates a windfall that wouldn't have been there otherwise. Whether it's because you were sitting on a bond that was impossible to sell and now you have money because you sold it, or because you would have gotten $1000 for it and now you got $1200, that's a windfall.

Whether that money goes into buying groceries or buying other securities, I assume most of it will continue to circulate in the economy. If it doesn't, then it's pretty much a failure as a quantitative easing.