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 :

An excellent player should aim at point A
(approximately) because he is almost certain to hit Single ‘3’ and then
he will have 16 to go out. (Players of all abilities should usually try to reduce
their score to a power of 2 such as 2, 4, 8, 16 or 32 – for the obvious reason
that they can aim directly at the double; even if they miss and hit the single, they
will still have a double to go out.)

A good player can’t afford to aim at point A
because he has to worry about hitting Single ‘19’ which would cause him
to go bust. So he should aim at point B (approximately), on the border between Single
‘3’ and ‘17’. If he hits either Single ‘3’or
Single ‘17’, he is left with a power of 2 to go out.

An average player has an even higher chance of hitting
Single ‘19’. So he should aim at point C (approximately). He will not go
bust if he hits ‘3’, ‘17’ or ‘2’ (unless he hits
Treble ’17’) and may well be left with a power of 2 to go out.

A belowaverage player who aims at point C might easily
hit ‘19’ instead. So he should aim at point D (approximately), a little
further away from ’19. He will not go bust if he hits ‘3’,
‘17’, ‘2’ or ‘15’ (unless he hits Treble
’17’ or ‘15’) and may well be left with a power of 2 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 BelowAverage 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 

The Darts Assistant can’t figure out
exactly what you should aim at until it knows exactly how accurate you.
General terms like “Excellent” and “Good” aren’t
precise enough. It needs to measure your accuracy on a numeric scale, the DA
Rating.

The Darts Assistant needs to take into account all of
the bad things you might hit, not just Single ‘19’.