I'm all about upvoting other comments to encourage the interaction you're talking about. When you upvote your own comments, it can be seen (by some) as increasing the noise and decreasing the signal. Obviously the author (in this case) thinks the comment is valuable or they wouldn't bother writing it. What matters is what the network thinks. That's a true signal. Sometimes I don't upvote a comment if I see they've already given themselves a self-vote.
I'm a little disappointed they removed the option to decline payouts on comments so you could still get the visibility, but it was apparently a bit to complicated for most users.
Ultimately, people can do whatever they want, and they will have the reputation their actions give them.