The guild itself wont make you money for a very long time, since the bank slots are not free. Though that is one of the big benefits in my opinion.

To be clear, when you get the guild some cash flow and unlock the instance challenges, you start making some money. So you make 10% g looted + (125g*7) per week. You can get those few levels pretty quick a day or so if you just do the low level stuff to 12-15 and repeat on a team.

Hitting all the instances, scenarios and raids for gold is a lot of work, definitely doing just for the gold.

Also the gold looted off mobs just isnt what it used to be, when the achievements first came out, the old world raids dropped a lot more gold for example. I am not sure if the AoE loot nerf impacter gold as much as it did other items.

Most of the gold awarded now is through other means that picking up off corpses.