I'm not so sure I'd say good strings make the bow more accurate so much as I do know they make the bow more consistently accurate over a longer time. Good quality strings that are prestretched and twisted properly won't creep near as much as poorer quality ones, therefore the tune of the bow doesn't change as often or as drastically. In fact, it's been my experience that with good quality strings, once they are shot-in and the bow is tuned there are very few if any adjustments ever needed during the life of the strings.

This statement only hold true for the strings I have used to date. That being Prostrings, Winner's Choice and Bucknasty.