Average accuracy certainly correlates to playing strength. But applied to individuals, it doesn't tell you as much. Players with a solid style will have higher values than those who prefer a sharp style, I'd guess. It certainly does not help with improvement: if your game improves, your accuracy also will. It's also true the other way, but how do you practically improve your accuracy?
How important is accuracy?

The winner almost always has higher accuracy. Also, the higher the rating of the players in a match the higher you'd expect the accuracy to be. Someone posted a chart linking rating to accuracy recently. You might be able to find it or if you're lucky, it'll get posted again.
Yes you should you try to improve your accuracy. That's the purpose of analysing your matches. In particular eliminating mistakes and blunders will have a dramatic effect on your rating. Then you'll also want to work on inaccuracies. For now I'd say you should forgive yourself your inaccuracies. Perhaps the exception here would be the first inaccuracy, which indicates you could have played well deeper into the opening to set up the mid game.
Someone with more experience might interject here. I'm just working this stuff out myself.
I have noticed that when I am winning games, my accuracy ranges from between 65 and 98 percent. Obviously, therefore, the relationship between accuracy and winning is limited, and it depends on the accuracy of your opponent, too.
My question is how important is the accuracy stat? Is there a certain link between accuracy and rating - e.g. A 1800 player would have 85 percent accuracy, a 2000 player would have 92 percent accuracy etc? Should I work on improving accuracy as a way to improve, or forget about it?