Playing GNB a bit and it soon felt like their gameplay mechanic was a bit pointless. Since your powder combo is mostly cooldown gated, you have no way to use it defensively, and your normal use of it is all pure damage they could have just made the combo purely cooldown based, made fated circle a third button to your aoe rotation and burst strike a fourth button to your single target rotation. With this nothing would have really changed other than bloodfest losing purpose.
Without something there with the powder gauge to actually choose to use, it feels completely useless, tacked on even; like its just there to give GNB a gauge of some sort.