That's not how I read that, it says "spend all of her remaining grit points (minimum 1)" which to me looks like a minimum on how much you spend, not how much you end up with. If the minimum 1 was how much grit you ended up with, it would be free if you only had 1 grit. Am I reading that wrong?
Either way, not a gamebreaking ability, you might get killed less because of it, but you'll probably still get killed sometimes and at the level you get it a raise dead is pretty trivially cheap. Not that it should have much impact on tiering anyway, they get it at level 19 so it doesn't see much actual play. Even level 15 abilities won't come up much.
Edit: I'm dumb, missed the capstone. The only question then is, can you reduce the cost of an ability that doesn't have a fixed cost, only 'however much grit you currently have?' Probably yes, just wondering if that got FAQ'd at some point.