If that is the claim, then why not do it with every ability. Why not do it with strength. For example, as a player to describe their character: "I am muscle bound, weight three hundred pounds of ripped lean muscle mass, and have 25" bulging biceps. But I have a 6 strength." Or, "I am lean, move like the wind, double-jointed, and walk with perfect balance and grace. But I have a 6 dexterity."
The reason to add it, is the same reason you have these broad definitions in the first place. To help the player describe their character and have it attach to something concrete in the game - which is what abilities are all about.