Interesting that it's rationed both by rolls and usage. What happens on a failed check?Here's the basics of the system in question:
Luke Crane has a nuanced discussion of this, in relation to Wises, in the Adventure Burner. It's tricky. I think the number one rule is, if you're saying No, be upfront.I'm personally not a fan of the ruin the story or veto for story reason stuff. I mentally edit that stuff out when I run it.
EDIT:
This also seems relevant to the "Once per scene" rule.I'm personally not a very big fan of currencies that don't have a corresponding fictional existence. Stuff like Willpower in World of Darkness is fine. So are strings in Monsterhearts. Mostly I think we rely too much on currency to mediate authority when directed judgement generally works better in my experience. Generally roleplaying game design seems overly afraid of its players. That we cannot let characters do amazing things without somehow limiting it. Pathfinder Second Edition and Exalted Third Edition have kind of changed my mind on that point. Nothing breaks if characters can just kind of be good at the things they are good at pretty much all the time.