A table like this is useful for those of us who count the carbs we eat.
It is definitely useful for those of us who calculate our insulin based on what we eat.
But, as
@ianf0ster mentions, we all react differently to those carbs so it is best to test the effect on ourselves.
Even when injecting insulin, different foods can digest at different rates (e.g. pizza) and my body seems to be able to extract more sugar from some than the carb level suggests.
Due to this variation, I don't get hung up on precise carb counting. When one person can react differently to a food than someone else, when some carbs are digested slower than others, when other things that are harder to measure affect our BG (e.g. stress, exercise, illness), when BG meters have a 15% tolerance, ... accuracy is not worth worrying about. It is one approximation on top of another.
I am not suggesting carb counting is a bad idea. But I am suggesting that it is not worth worrying whether apples are 14g carbs, 12g carbs or whether it varies per type of apple, the ripeness of the apple, how much of the skin you eat and how close you get to the core.