@Mothified BTW, where do you think the salaries for the servants go and where they come from? Especially since servants aren't the only employees in the system.
And even in the capital not everything a noble buys comes from the exclusive shops (especially since those shops have a very limited clientele). Most of the time servants just go shopping at the local markets to keep the estate stocked. Not to mention even those exclusive shops have employees, of course.
My point is, while those funnels for the money from the general cashflow towards the rich's coffers certainly exist, the whole point of the Yuuji's spending through the bunnyhouse is the fact that he adds a new flow from those coffers back to the general cashflow. And while that, in turn, indeed enriches the rich somewhere further the chain, it still add even a bit to the actual exchange of goods and services, and that in itself makes the lifeblood of the4 economy.
So while Yuuji isn't the centralised sewers, at the very least he's an emergency pump.