Good point. Although there are some other areas of trading where speed matters that aren't HFT. An example is the algorithms used to split up large orders into

Good point. Although there are some other areas of trading where speed matters that aren't HFT. An example is the algorithms used to split up large orders into smaller trades in order to hide the position and have a minimum impact on the market price. These are often optimized for very low latency as well. Especially the more sophisticated versions that do things like halt execution in the event that there is news on the stock, etc.