HFT provides liquidity, makes markets more efficient, prices more accurate and narrows spreads. Moving money around as accurately as possible increases the accu

HFT provides liquidity, makes markets more efficient, prices more accurate and narrows spreads. Moving money around as accurately as possible increases the accuracy of allocating funds where they should be. Everything in the World and economy is connected. Accurate prices, efficient trading conditions allow for better allocation of funds on targets worthwhile pursuing. On the whole you can think that there's Company A and Company B, where both produce different amounts of value. There's an optimal state of how much each company should be funded in order for optimal value production from both together. The more accurate you are with allocating funds the best are the gains. So in that sense it's not zero sum.