Coins are not the point of the game! They exist as little bonuses that can help you along, slightly. You gain much more mood, xp, and currants from completing quests and actually interacting with the world.
I kind of loathe the quoin limit, but it has stopped me from being greedy. When I'm at 430/450 I don't need the energy quoins. Just like I don't always need the mood ones.