"If you're scrawny it's because you don't work out hard enough" feels like a not great message? I would love everyone to have healthy habits and get better at physical things than they are with unhealthy habits. On the other hand the vast majority of people will never be an Olympic level athlete no matter how hard they try.
Granted, but it still means that a D&D character is practically near their peak potential at level 1, with no way to grow beyond that sans magic or leveling. You can't just decide to hit the gym or eat better. Which is still better than pre-3e, where magic really was your only recourse (unless you're a Cavalier, for some reason).
Ability scores are an abstraction, to be sure, but the fact that they don't work like real life makes it difficult to compare them to actual traits real world people possess at times. The "charisma/appearance" debate being just one facet of this. D&D doesn't really model the "good at one aspect/bad at another" of ability scores in any real way.
You can say you have massive hotness and a terrible personality, but your Charisma modifier remains the same for all purposes. You can describe your high-Wisdom character as near-sighted and gullible, but possessed of an indomitable resolve....and you still have the same modifier for perception, insight, and wisdom saves.
Previous posts mentioned this; "what is your Charisma in the dark? What is your Charisma to a deaf person?" And the answer is, exactly the same as it always is. Again, as previously brought up, your Sorcerer's magic saves and magic attack are the same whether they have the appearance of a Greek God, or the commanding voice of a mighty leader.
Because the game does not model these differences, any attempt to say "my ability score means I'm this, but not that" ends up having to be ruled on a case-by-case basis, if at all.
As a result, character traits =/= ability scores. One can be informed by the other, but the actual score doesn't change. Now perhaps someone could add a "boons and flaws" system to the game, but the fiddly, small bonuses here and there likely granted by these would add complexity to the system that I don't think many people really want.