If I am holding a one hundred dollar bill it is because I performed a service to someone else that they valued more than the dollars.
Yeah you did! It's what they like to the 'certificate of satisfaction'. Nothing like a happy ending
Think about it this way
1 - $20, fastest: 10million shares of company X, starting value $20, market cap: 1billion shares. Cost raised 1%
2 - $20.20, 1.1ns slower: 50million shares of company X, cost raised 5%
The second purchaser cost just went up 10million dollars, when you are making trades hundreds of millions of times a day the difference can be billions of dollars easily. Then again, it's making rich guys richer, but a fraction richer, I'd say no. It's a huge deal worth paying for the best programmers, engineers, etc.