Karma teaching useful in training the mind so that it can put an end to suffering
"[The Buddha] doesn’t give a complete theory about how everything happens in the world and can be traced back to particular actions. He teaches karma to the extent that it’s useful in getting the mind to be trained so that it can put an end to suffering. That’s as far as his teaching goes, but that’s pretty far. It’s much better than having a map to everything but still suffering. So use these teachings to take you where you want to go because they can take you farther than you can imagine." ~ Thanissaro Bhikkhu "A Meditation Karma Checklist"