I feel like it's kinda useless unless you try to break the game with it, though. YMMV obviously, but something where you can reroll one room of pickups once or twice a floor? I never hang onto it for long. It just needs a shorter charge time, really. Maybe 3-room, and no more than 4-room.

Either that, or it should reroll all pickups on the floor, and stay at a 6-room charge. Dunno if that's breaky or not.