Concoction Skills are banned from using heralds?

I am not sure if this is really intended or if it is a bug, but I cannot imagine GGG seeing and nerfing any aspect of Unarmed just to also exclude them not only from the only seriously good defensive spirit buff for evasion builds "wind dancer" as much as it feels hard for me to understand if they take away all possibilities of clear through proliferation or ele explosions for the other Conc skills.

Only PCoC is able to prolif and also only if we spec for it in ascendancy and it is literal trash compared to the herald of plague? Herald of Blood seems to be made for BCoC... yet we are not allowed to use em since we have the wrong "weapon type"?