HFT contributes to making the market. Making the market contributes to liquidity and the ability to get in and out of things quickly without taking major hits.

HFT contributes to making the market. Making the market contributes to liquidity and the ability to get in and out of things quickly without taking major hits. This seems abstract until you think of cases other than stocks where you desperately rely on a market -- 1. Think homes. Consider buying/selling a house and how painful it is to keep something on the market hoping to find a seller (often at a hit if you want to unload quickly.) Or a buyer desiring to purchase something only to have a handful of homes come on the market. 2. Imagine if for every book you read, you could quickly unload the book (or buy new ones) without fire-selling and paying an absurd shipping cost. HFT and market making reduce friction. They are market lubricants. 3. Imagine looking for an apartment to rent and there were a perfect curve of apartments a dollar apart available all the time!