My payout on that post should be about 23 LEO vs the 7 LEO spent, the post was already at 5 LEO before I promoted it, so the gain from promoting is 11 LEO at a glance but the post was curated by the Leo curators afterwards as well so that muddies things up a bit.

As such, it's not clear to me that promoting returns a financial gain, but it definitely does get more eyes on your post.