More often than not an informative comment, while maybe not being downvoted, won't be the top comment. Instead, you'll see really low effort "zingers" which make it to the top. Those are further piled on with a flood of comments trying to one up each other.
So, you end up often needing really strict moderation to curtail this problem.
Chrono ordering suffers the same issue, somewhat, though it doesn't have the pile on problem (not to the same extent).
Take my upvote!
Here's gold for you good sir, hearty lols!
The Reddit/HN format makes everything time sensitive. If the post falls off the front-page, nobody will even see your comment, the discussion immediately dies. It's completely unfit for longer form discussion over time.
Sometimes you want a forum for discussion, not just a comments section of highlight reel one-liners.
One of the games I like to play has its own forums and they are still the best source of info compared to reddit. Discussions are surprisingly readable, though that may have something to do with the older target audience.
Voting, for all its problems of bias and agenda driven voting, eliminates 99% of the chaff that makes chrono-forums unreadable.