"Charisma is about sex appeal" is funny, but that's not really entirely accurate. It's about motivating others towards your goals whatever that may be, having a presence that commands attention and being a good communicator. That's why charisma helps disparate skills like lying, persuading, intimidating, and performing. Sex appeal may superficially help some of those things, but so does a half-giant that makes you piss yourself with their mere presence, or an old fat guy who speaks with clarity of conviction and intelligence. Ain't nobody want to fuck Winston Churchill, and he was an asshole as well. But he was a very charismatic figure, still.