The Steyr ACR is the gun the Pallet Rifles in EVA are based off of, and this one is about as useful. On one hand, it seems like she'd be good for para fairy and its debuffs (you get +25% final damage with that), except it isn't enough to make up for the debuffs still. It's also not very easy to get debuffed. Evaluation may change based on future enemies, but really it's not worth it when you have so many good ARs to choose from.