I think the real question should be, what is the benefit of the blue / purple items compared to the green ones.
For example, you could drop one of the mission crew skills for say slicing, or another crafting one and not worry about building blues / purples. I know for the rapid levelling until about level 15 or so, RE the armour or stims was not worth the cost in materials as the next available item would be much better. But as you get to 2-3 tier items then it seems to get better.