Simply it works! Probability - If your cards have 60% of chance to win, you can win in the most times for value, if your oponent folds 80% in that spots, you probably can win for a bluff. Equity - Your pot odds have to be equal to your odds of win. Implied odds - Your call should be equal to equidade between your cards and the total of chips you get earn of villain.
(excuse for my english)