I can think of quite a few times having 30 bullets was helpful. You're ct on mirage A, kill one ramp, hide, kill another, hide, then maybe peek again and kill palace pushing out. No reloading inbetween cause it all happens so fast.
Or maybe clutch situations? Burst one down, turn around and kill 2 others maybe with spray transfer
Maybe that's just my impression cause ppl at my shit rank don't immediately kill you :D