Amazon Penetrate node - am I misunderstanding something?

"Attacks using your Weapons have Added Physical Damage equal to 25% of the Accuracy Rating on the Weapon."

I'll admit, when I read this the first time, I thought it would simply pull your accuracy number from the skill screen for whatever skill you were using, and add 25% of that as flat damage to your attack. But I allocated it just now and ran around for 5 minutes - I can tell you that my tooltip did not change at all, and it felt like my damage in-game didn't either.

Is it really referencing like, a local accuracy affix on the weapon, meaning 25% of that? I didn't have a spear with an accuracy roll laying around to test. If that's the case, is this node even worth taking? Accuracy is a prefix and competes with phys rolls..