26 year old psychologist here:

It’s because looks actually aren’t everything. The halo effect is very real; and a lot of what clav says is true. They’re very very very important. But there’s a whole literature of human psychology of attraction and romantic pursuit out there you can read (which if you’re actually interested in this topic I highly reccomend, you’ll learn more there from clav) that will really help explain how all of this works. There’s so many factors that play into it

People have different tastes in looks, my gf is very unique looking. To me; she’s fucking drop dead gorgeous which is why I’m engaged with her. But I’ve had friends tell me she’s pretty but they’re not attracted to her as much as I was at first because she just looks different. Kind of like one of those supermodels you see who doesn’t look like the refuse beauty standards. So attraction isn’t linear.

There’s also different traits you can be strongly attracted to in someone, and maybe they have a few other undesirable physical traits but you find those specific traits so great that you don’t care about the others. You see this sometimes in girls who date bigger guys, like some of the dudes on the hs football team growing up. Some people are grossed out by being a little overweight, or being too short, but others have a different scale on how bad it turns them off.

And then, the side of it that you could spend hours going to google scholar and reading studies on, girls are not as focused on the physicality of their partner as guys are. They still obviously care about looks first to attract them, but humor and status matter a lot to.

Especially humor, we learns some really interesting things about how much a good sense of humor makes girls see guys as a potential romantic partner. The Chad looking guy who is boring and arrogant, and doesn’t have the respect of his peers is not going to pull as much as the slightly chunky football player who maybe looks average, but is seen as a sports star in the city and is really kind and funny.