Im able to get better weapon without using the coffer like 10=10 at level 3.
So if you know how to earn golds from forest,non cityhouse user wont affected much.
But i think it's out of topic. 
My reply to the key to coffer is..Okay.
So you can give a place to your clan member to sleep and your golds wont be wasted much..
But remember some player may insulted by not given the key to coffer and they may plunder your dweling in order to "pay back"... 
Unless keep powerful guards to protect it .
