In the past, early voters (before 30 mins, now that has also changed to 15 mins) sacrificed some of their curation rewards - those went to the author, so some people didn't mind and voted that way as some extra author payout. However, now such lost curation rewards just go back into the general reward pool, so benefits neither the author nor later voters.

I wrote two short articles, the latter one is here.

For self-votes, if you vote after 15 minutes you will also get some curation rewards, just like any other voter; if you upvote before 15 minutes then, as I sad above, any curation rewards go to the general pool.