I think its fine upvoting your own comments if you're an investor of this platform provided you will follow an acceptable time frame to get your ROI. In that range of time, you should put value to the system and appreciate the community thru giving some influence. In that case, it's a win win situation and no abuse will be practice.

In regards with ordinary user that built up their own empire(becoming a dolphin), its also allowable to upvote your own comments for you're putting so much time in the site and provided that you're re-investing it to the system and giving back something to the community.