That's not my point. Of course articles are the most valuable part.

But how does it make sense to give 400 points to a submitter out of 5 who posted the same thing ? And often to an article which may not be neither the first, nor the best about the issue. That's what I mean by entirely random.

Furthermore, without threads and comments HN would just be another link aggregator from some relatively fixed sources.

And you prove my point about comments mentioning a-holes, in that useless ones would be downvoted while useful or informative ones would be upvoted, and quite rightly bestow karma and benefits to contributors deserving it. That would make sense. You wouldn't see actual a-holes, they'd be downvoted to oblivion.