What it means
Humans can't compete on speed and don't need to: trading on minutes, hours or days makes microseconds irrelevant.
In practice
High-frequency firms act as modern market makers: they quote both sides, trade tiny edges millions of times and keep prices in line across exchanges. Their presence is much of the reason spreads in liquid markets are so narrow.
For a discretionary trader the practical lesson is to compete where speed does not matter. A setup on a 15-minute or 4-hour chart depends on structure and patience, not on reacting within microseconds.
What to watch for
Scalping for a few ticks puts you in direct competition with machines and makes costs the largest part of every trade. Fast liquidity can also vanish in a shock, which is when prices jump.