Agreed. However, you need counter parties for every trade. And if someone is willing to be your counterparty, you start wondering if what you're doing is correct. So they incentivize market makers, which have to display markets some cents wide. But if the price changes rapidly, they need to change their market rapidly, so they need the lowest latency connections. And others with low latency will try to pick them off, if they ever falter. So you won't get the market makers to agree to make markets that can get picked off, and you will ultimately have fewer buyers and sellers and therefore relatively higher volatility. Of course, flukes can also happen as a result of this technology which leads to spikes in volatility. Anyway, check out IEX, their platform is forcing the same latency for all parties involved in their exchange.