As much as anything, I come to HN for the comments and the expertise of the crowd in general for subjects outside my particular areas. If I don't have time to read an entire argument/thread or study a topic in detail, it can be useful to see the prevailing mindset. Sometimes that is akin to consensus.

Would be interesting to be able to enter a thread being able to see the votes but not vote, or voting without seeing the results. First time you enter a thread, that choice is locked in so you can't straddle the fence.