The comment vote disappearing (in most cases), isn't exactly encouraging engagement. I have stopped dishing them out and am feeling a little mean for doing so.

I wouldn't say the engagement has ceased, but it surely was an incentive for other's to comment on my posts, in anticipation of that vote.

If and when the STEEM value increases, then I can do it again.

I'm speaking probably in a minority as a decent sized stake holder. Many other's will have more moans than me. Curation is up by a long way.