Why does it need to know how accurate I am?

Take the example of a player who has 19 to go out at the start of his turn :

19 to go out

To summarize : you should aim approximately at points A, B, C or D, depending on whether you are an Excellent, Good, Average or Below-Average player. This shows why the Darts Assistant needs to know how accurate you are before it can tell you what to aim at.

But notice -