As you go through the level you may find prize boxes with nothing but heat and CR in them (this makes the level and battles more difficult) and I can understand why you did that.
Once you beat the mission however you have a prize room in which you have numerous boxes. As a player I feel it is a bit of a slap on the face to find things like Vitapods and HP capsules as well as other pickups when I should be getting as big a reward as possible (or at least one that is the maximum output for the number of boxes presented) considering I just went through one of the toughest, cheapest, and laggiest battles in the game.
What is the point of boxes dropping things that I will never use?
That might be a side-effect of the boxes dropping fire crystals. Personally I'd rather have the ability to have fire crystals but also get consumables than have no chance of fire crystals and no chance of consumables.