This concept is most important in no limit play, where it is possible to bet all your money early in the hand. One must judge not only whether your opponent's hand might be better than yours, but whether or not it might dominate yours to such a degree that long-run fluctuations of luck will amplify the consequences of a mistaken play rather than mitigating them.
One of the things that makes no limit Texas hold'em strategically rich and interesting is the unusual relationship of advantage and dominance among various Starting hands. For example, the hand A♣ K♦ is a slight favorite over J♠ 10♠; this hand is a slight favorite over 4♠ 4♣; and in a non-transitive relationship, the fours are a small favorite over A♣ K♦. None of these hands dominates any other, but A♣ K♦ does domimate A♥ Q♦, 4♠ 4♣ is dominated by 7♠ 7♥, and J♠ 10♠ is dominated by Q♣ 10♣.