(Lots of rambling to follow)
Many ability scores in D&D have issues. Charisma, historically, has been one of these, as it generally governs only one thing- social interaction with NPC's. Using Charisma to interact with PC's generally has a lot of pushback ("What? My character would never back down from this guy!"), if it's allowed at all. For example, the 2e PHB has complicated rules to govern adjusting the way NPC's react to you, and the only "social" Non-Weapon Proficiency is Etiquette, which doesn't actually influence anyone- it just lets you know what you should do in an encounter, but doesn't actually prevent you from messing it up ("The encounter must still be role-played by the character. Knowledge of etiquette does not give the character protection from a gaffe or faux pas...").
In many games, unfortunately, Charisma did very little. And quite honestly, when the game evolved to making social rolls a standard, it actually hindered role-play more than it helped; even if your character was highly Charismatic, and you role-played accordingly, quite often your epic speech was reduced to "ok make a die roll with a bonus...oh too bad, you rolled a 3".
Charisma was a very bad ability score, and the 3e design team noticed this, and so, Charisma was given active things to do. Paladins and Sorcerers used it to determine the power of their class features (oh and Clerics too, for Turn Undead). Monsters used it to determine the power of spell-like abilities. This trend has continued to this very day, as many attempts have been made to justify Charisma as an ability score.
Even though 5e has less uses for Charisma than other versions of the game, you can still figure out how to get Charisma to attack and damage rolls with a weapon, several spellcasting classes are Charisma-based, Paladins still get +Charisma mod to saves, and Swashbucklers add their Cha mod to initiative. All we're missing is Charisma to AC and we'll be pretty much where Pathfinder is.
And I understand how that annoys people, especially when you compare Charisma to other ability scores in 5e; Intelligence has very little use- Wizards, Eldritch Knights, and knowledge checks. The going design seems to feel that every attribute governing a save is enough to justify this- I'm not so sure.
Strength is somewhat devalued by Dexterity, which is as strong as it ever was, and Constitution is still in a very strange place- while Con saves are common, and it affects hit points and regaining hit points by spending Hit Dice, it has few active uses, and from what I have seen (anecdotal evidence, but it's all I have), spending an ASI to raise Constitution by 2 is not generally a great advantage compared to other things (yeah yeah, I forgot that some people can use Con to boost unarmored AC, but high AC is so easy in this edition I can't really blame myself).
If Charisma has a right to exist in the first place (and I'm really not sure that it does, other than "D&D has always had Charisma, it wouldn't be D&D without it"), then yes, it needs to do more than govern interaction with NPC's. Especially since a Rogue with 10 Charisma and Expertise with [insert social skill of choice] is better than a guy with 20 Charisma. So the current trend of buffing Charisma and making it an attractive option is fine.
However, the same amount of options should exist for other ability scores, such as Intelligence. The way the game is at the moment, you can make a Fighter with Dex and Con of 14 and all other stats 10 and be just fine*. But if you want to play a Monk, you're going to need Dex/Con/Wis as high as you can get them. This skews the balance of the game tremendously, and point-buy arguably makes it less balanced, not more.
*Assuming that you're ok with letting other characters handle the non-combat aspects of the game- we have other threads to talk about Fighter balance. And yes, I'm not forgetting saving throws, but proficiency matters more to successful saves at the higher levels of the game, than a Fighter randomly having a 16 Wisdom- it's nice to have, but there's a very good chance it might not matter much when save DC's in the high teens start showing up).