The omega male knows how important looks are, because he was refused because of his looks numerous times.

The alpha/slayer knows how important looks are because he had all kinds of girls attracted to him because of his looks. Many of these girls were willing to make out/have sex with him from the very first time they met and before they knew anything about him at all.

Everything omega and alpha males say and do are heavily haloed/failoed by their looks and (unless they are extremely low IQ) they notice how certain patterns of behavior are perceived completely differently when they follow them.

The beta male can also notice that looks have an extremely strong impact on how people are perceived (many do) but it's less obvious to him.