Beauty is in the eye of the beholder. One may find a dragon beautiful, another not. Yet the dragon has the same charisma to both.
Until one brings in the rather obvious idea of Charisma being different based on species preference.
A Beholder, for example, might be Charisma 15 when dealing with other Beholders but come across as Charisma 6 when dealing with anyone else. (for game purposes its Cha would count as 6)
This becomes more relevant when dealing with PC-playable species who culturally don't always get along and-or who generally find another species more or less attractive than their own. A Dwarf might be Cha 18 in the eyes of other Dwarves but come across as 16 at best when trying to negotiate with a room full of snooty Elves and other non-Dwarves. (the game would count the Dwarf as Cha 16, species-adjusted down from the 18 that was rolled there)
On an individual level, sure - a person might run into someone with Cha 18 and be thoroughly put off, while that same person's best friend might only be Cha 9; that just comes under people gonna people.
I also know people who are very fair of face and form but just damned annoying to deal with. They don't have Charisma, even though they have beauty.
Same here; and to me those people would have, if statted out for game purposes, an average Cha score made up of two rather extreme elements.
I remember one person I knew - I've never known anyone better at making a good first impression, and at the same time never known anyone worse at making a good second impression.
If they were split out, that person's scores would have been about Comeliness 18, Charisma 6. Combined, the net result was about an 12, i.e. only marginally above average.