I do not know the actual way it works because its not something that is worth it to me, nor other players also,but I would suggest Its called bait,and if you analyse the game, its full of it. 

Everything gets more difficult and costly as you progress, and the idea is that you get used to something and cant do without it,so you just pay  because you cant do without it , or wont do without it, or haven't even noticed that its gone up, or that you are spending to much money on the game until you add it all up or see your next  bill.

well its ridiculous because buying a pack gives more reward (e.g. hero and shaman energy) than the northern brotherhood additional rewards would be for 15 - 100 point monthly quests and less than half the cost.

while I have been enjoying the game, doubt I will be bothered pushing past palace level 30 and certainly won't waste any more cash.

How does it works? If i enter from the weekly event i will get rewards only for the weekly checkpoints or for all of them (monthly, weekly and daily)? Thanks!