Am I missing something? There's no arbitrage trading opportunities as far as I can tell so what cargo are you supposed to be hauling? Piles of looted succulents and notepads?
(Serious question! I like space trading games but I don't see that as a thing and I really am curious if I'm missing something.)
But dropping the argon inside your ship might also count as cargo. Decor items like weight-plates, dumbbell etc uses up cargo space. Will try it once my Aluminum storage is full again.