Eh, when it's tied to spell casting, appearance is the least factor, and not every dm uses it for that (I didn't and don't for regular d&d)

And it is tied to spell casting in multiple ways, across multiple classes. So that means it isn't real world charisma. Mind you, that's also ignoring how much real world charisma is appearance based. And it is a major factor in the real world, which may explain why you used so many characters as examples.

D&d, RAW, says charisma is a stat that allows people to use magic. Same as wisdom and intelligence. That is a huge issue. Intelligence is explained as being the tool because the characters learn magic using the mind, and cast magic via mental skills. Wisdom gives the character the ability to interact with a source of power by attuning/worship/"grokking", and thus use magic.

Charisma? They charm the magic out of the air? At least with warkocks, that makes thematic sense. Their personality allowed them to convince something to give them power. But bards blow that out. How the heck does their personality make magic happen? It doesn't.

So, opinion here, either the decision was made, and was a bad decision, or the decision was made for a reason, but the stat no longer represents a real world ability at all, just like wisdom doesn't (and never did, really, imo). At least with int, you can pretend they're learning the underlying forces and techniques to allow what they do.