I don't think making BP usable outside of Grit would make it more useful, when outside Grit we have access to Blood Weapon, which is way more reliable for MP recovery AND it also boosts damage. Whereas BP gives us MP when hit, and it's also not very much. And in an OT situation where there's no adds, I.E. we arent getting hit, it'd be useless. One way to make it useful is to increase the amount of MP we get per hit and possibly add a little bit of damage reduction for the duration of the skill(5-10% maybe), would make using Delirium on it worth it.