Fury Leap / Crushing Impact increased stun chance

New player here- I'm confused about the following: Nowhere does the game specify that Fury Leap has a stun chance, yet there's a node Crushing Impact which increases the stun chance.

I understand "increased" means that if my original stun chance was X%, then after taking a point in Crushing Impact, the odds would become 1.3 * X%. However, if there was no stun chance to begin with, then it's still zero, right? Am I missing something? Does taking this node only make sense if my weapon has a stun chance?

I'd be thankful for any insight on this!