"Because we can and it's free"

Hoard Crystals, Diamonds and Steel in preperation for Item Maker

This. well, not this specifically, but the easiest and best way to make money is to educate yourself on what might be in demand after a patch and to stock up on it in advance. Then, sell off your stock the day after the patch. If you knew about the quest in Singapore which needed Emeralds, for example, you could have bought up a lot of emeralds and then sold them on patch day to questers for a lot.