Hat tip on saying comments with karma removed are point-less. ;-)
My experience is the opposite of yours. I find karma as it has become here recently is not a reflection of good counterpoints. I feel it has become a reflection of the popular points. Well argued counter points, if unpopular, are "voted down".
Assuming the thread sorts by karma, you can still read in order, and get what you're looking for, and maybe you'll read things that are less popular, not just the majority-upvoted comments.
Another comment here talked about score, a gaming term. I don't like the term "score". Like you, I value thoughtfulness and interestingness, whichever side of a point it comes from.
In user profiles, karma can work as a gaming feedback mechanism to encourage desired behavior, while in a comment thread, it can work to surface insightful discussion and bury non-contributory content. A display of "score" isn't needed for the second mechanism, just good sorting.
However, it seems that a refinement of seeing your own 'score' on your own comments could be valuable towards the first mechanism: "How was my comment received?"
That dopamine hit is valuable to foster recurring contribution.