I have been upvoting comments in my posts lately because i can now use a 5% upVote and it will have .03-.05 cent and higher if it's an exceptional comment.
This has shown to have a positive effect on Engagement because they know that the better Comment they give the more that I would reward.
As for Comments I have started upvoting those comments that add value and add my own comment to it.
Not a lot of people do that among red fishes and minnows like me because of the limited VP and value.
Goes back to a scarcity mindset of some people that they want their own comment to go up so they feel that if they would upVote on others techy will have a less of a chance to get their own comment upvoted.