This is an interesting topic for sure! It seems like I haven't had the same experience as a lot of people here, I feel like I see people get treated differently based more so on their personality.
I think I'm a fairly decent looking girl, though I don't always put the most effort into my appearance, but I think I come off as fairly "distant", or not super approachable to people who I don't know well (really I am a little bit shy and can be kind of antisocial, it's not that I actually think I am above people at all...), so though people are perfectly decent to me, I don't seem to invite a lot of chattiness or connection through my daily life. I will still get hit on out at the club, sure, but I don't for instance strike up a lot of conversations while out doing errands.
However, a few of my family members and some of my close friends are just super chatty and outgoing, and they make best friends everywhere they go. Sure, they are nice looking, but I don't think that has as much to do with it as just the vibe that they put off, and the effort that they put into making connections.
I've had quite a few friends who weren't necessarily conventionally "hot", but were just super attractive to other people because of the way that they presented themselves.