I think he means that he has a better chance of winning the pot if he's on a rush. Implicit in this statement that he can win the pot without hitting his hand. Since he is going to make a continuation bet almost every time and people are less likely to play back at a hot player, he can take the pot right there on the flop. If he gets callers he will likely buy himself another opportunity to improve to the winning hand on the turn with his continuation bet.

I'm giving Doyle a lot of credit for things he didn't say in this passage, but the general tone of his chapter kind of follows this line of thinking.