Here's my view on this. This thread is basically asking the exact same thing as the wit thread. It ultimately comes down to "can a person RP something, whether a trait or skill, without actually validating it through RP?" And as many of the people in the last thread said and how many of the people in this thread have said, it depends.
It depends on the person RPing. It depends on the people they are RPing with. It depends on how all of those people view RP and judge what they feel is "good" RP. The only wrong way is to not try or to have no imagination. A story and only go so far if the characters are lacking, and a character can only go so far if their story is lacking. The larger a list of do's and don'ts becomes, the more intimidating and difficult it is to follow. Ultimately, it just ends up with people trying so hard to fit into the "community guidelines" that they stop writing characters for themselves. And then it becomes unfun.
How does one RP that their character is smart, beautiful, able to drive a car, ride a Chocobo, fight, use magic, or do whatever else they want to do? They try to write it to the best of their ability. For some people, that might actually be writing something like "my character is pretty," or "my character is ugly," or "my character is really smart, but ugly". If they think that's sufficient to describe the character, and the people they RP with are content with it, there really isn't much of a problem. If that same person later goes "how can I better show these aspects of my character," then it's a perfect time to sit down and think about the character's intelligence and how it's show, about what the character looks like and how that can be written and developed upon. The game only allows a characters to look a certain way.