Well the main benefit I see from steembounty is more user engagement. Often times, especially in this bear market when steem prices are low, you can't even get a reply to a post or comment.
But with steembounty it seems that people try to post more meaningful comments so they can reap the bounty. Of course, you should comment even without the bounty, but unfortunately this is the only way currently to have more user activity.
I agree that it does promote more comments for articles because of the reward behind it.