Some of these people are high-net-worth individuals. I sometimes ask them why, instead of trading, they don't take that money and invest it in new research or technology or product development or services. At least then, there would be jobs created, technological progress, more money exchanging hands. But, to them, it doesn't make sense to do that; they make much higher returns, more quickly through trading.
To me, a lot of this money seems to be 'locked up' in liquidity trading, that would otherwise be doing good things for the economy and human progress. Right now, it doesn't seem like the traders have incentive to do other things with the money.
When a friend of mine 'clicks a button' and makes a few million from a trade, how is that adding equivalent 'value' to the overall economy than if he would have taken that money and invested it in a new start-up? Again, this is my total ignorance, but something doesn't seem right. To an ignorant person like me, it just seems like wealth exchanging hands, but how is clicking a button better than employing hundreds of people?