Many HFT systems provide liquidity. If there is no liquidity, retail investors like you or me cannot buy or sell.
Just imagine you want to exchange a currency because you go traveling and the exchange tells you "Sorry, nothing available right now, gotta come back in a few weeks". That's what would happen if there is no liquidity.
Just imagine you want to exchange a currency because you go traveling and the exchange tells you "Sorry, nothing available right now, gotta come back in a few weeks". That's what would happen if there is no liquidity.