Projectile Launch System (Cyberpunk 2077)

I came across numerous guides where they scolded this thing, I bought it and went nuts, the hand is naturally a grenade launcher and without reloading, I play a street samurai with one katana, just a perfect fit, cut in a slowmo from a sandevistan, shoot into the crowd from this wunderwafe and cut everyone into steaks.
Where does this thing get its cartridges from and is it really possible to discharge it? I've even thrown grenades, but she doesn't use them.