Been using this with my Bunny in solo bossing for taking out weakpoints on immunity phases.
The weak points on those phases either don't scale properly or count as a weakpoints hence why I have gone the higher crit dmg and chance on hit than the weakpoint dmg on hit, but it is another great option.
with 92% crit after weakpoint hit every round "should" be a crit for max dmg.
Have Fun!!