playing evil is extremely unrewarding, i would argue that it does not bring any new content the whole playthrough, it only cuts content basically, except possibility of recruiting minthara which can be done even if you play good durge/tav from what I read
I agree, there's no actual point in being the full evil route. Even the evil ending is so disappointing that there's no point tbh. However, Minthara can only be recruited if we kill the tieflings. there are mods to have her without doing it and there was a bug to have her and Halsin, but as far as I know, the bug was fixed already.