Tightening the spread reduces everyone's transaction costs. Successful algo trading takes money away from existing market making traders and splits that money w

Tightening the spread reduces everyone's transaction costs. Successful algo trading takes money away from existing market making traders and splits that money with those who need to trade for reasons of capital allocation, financing and hedging. It's straight up price comeptitive under cutting in the most darwinian way possible. Less money sticks to the financial system, more money in the hands of business to expand and build stuff. More money in your retirement savings. I think that's doing something.