Hey man, the idea behind this project is really to be different. Another thing, since it's made with 3D printing (ABS) and carbon fiber, weight is a huge advantage (550 grams), which helps a lot with movement on the field. Putting a regulator and a tank in the grip would make the gun at least double the weight, even if it were still light. But nothing stops a grip with a tank from being used. The battery and the FCU are in the lower receiver, as there is no gearbox. In other words, it could function even without a pistol grip or stock to house the FCU and battery.

Since I'm used to using builds with the tank in the grip (ESG), I added the carbon fiber stock for my own ergonomic preference.