Her ability probably won't matter much. Her role will be of a double agent. Honestly, fuck Tserri. Guy is a total psycho. I predict Borksen landing a hand to Kurapika.
Nah her ability will absolutely matter. That's precisely why they got her. Morena will hold her hand and develop the specific ability she wants in her.
Tho what Borksen will do with that ability is definitely the main plot point here. I believe Borksen will try to fuck Morena and heil-ly at first. But will have a change of heart once she learns what Tserry actually is and what he's capable of right now. As well as what he really thinks of Borksen and her friends.
I agree the she will be an ally to Kurapika ultimately. But that will come about because Kurapika will ally with Morena and Heil-ly to take down Tserry imo. I think even the troupe will ally with Kurapika and Heil-ly. And on the other side, we will have Hisoka nurturing and teaching Tserriednich.
So a makeshift alliance of Kurapika-Troupe-Heil-ly VS the Sinister Duo Tserridnich and Hisoka.
That's my theory at least. But who knows. Togashi be hella unpredictable a lot.