no not a single benefit. in the future maybe having a black heart with some other characters will make other characters trust/distrust you instantly. like if you use the love potioin on korg and get his black heart maybe rumors will spread among the orcs your a rapist or some shit and they will begin disliking you more and you have to earn back what was lost via the black heart.
or on the other hand having a black heart with... lets use Korg again might have some Northcrest people trust you more since orcs seem to REALLY dislike the MC. or other enemies of the orcs.
been a year since I said this but I've been looking for this comment to add this, this is all speculation on potential future content. it is not in game.