Boril also makes the Trial of Fortitude much much much easier. As the eligible classes are Cleric and Druids, it can be challenging to come up with enough striking power to kill the bosses. Boril solves that if you put up riposte and then set of Horghall’s special skill - often that will be enough to take out Horghall.
Boril is still eluding me but I am maxing Cyrian for the same purpose.
Btw, it turn out a ranger’s piercing hit can hit thorough the active riposte unscatched. Did a couple of time with Lianna on Elena. Risky business though. A dispeller is better.