Are there not enough gold faucets at present? If not, wouldn't it be better to tweak existing faucets that require player activity, rather than adding a new one that's entirely passive?

Only if the Npc bankers have to earn the money they give as interest through reckless investments, so there is always a risk that the gold and items in your bank will be randomly lost or the bank itself will liquidate.

On second thoughts let's keep it like a game.