I don't know what typical HFT margins actually look like, but is there a tangible benefit to markets being 1% more efficient?
Strong disagree. Liquidity at the level of milliseconds means insider trading and other information disparity is more profitable and encourages people to make rash decisions on incomplete information rather than well informed decision.
I'd love go see any information that proves that trades at the millisecond level lead to measurable improvements over, say, trades executing once per hour.
It might be harder for HFT to make money if trades were processed in random order on the hour, though they would probably still have an edge.
Online games that care about fairness try not to turn into a competition for the lowest ping time.
The government abandoning free tax filing software is GREAT for Intuit - they make a lot of money off it. It's awful for the rest of the population and the country as a whole.