785.000 silver coins and growing. Two more shifts for half an hour could well be worth 3,000 coins.
The Tavern needs changes in tablecloths, chairs, adding floors to the Tavern, bedrooms, improving the drinks, having workers in it who are responsible for picking up the tables ... an assistant to choose for 3,000 / 4,000 / 5,000 coins per month and that has added qualities, such as giving attack bonus and defense to your city (all quarrels were always there drinking), reduce the time to visit the tavern again because the waiter is a very high beautifull young or the waitress is an angel, another who gave more tips ...
Silver coins could be used to buy special buildings from previous events, buy missions that give something decent as a prize, ...
The Tavern was always a meeting place for adventurers but there are no "adventures" in it. Paying silver coins for some decent adventure, no event, would be fine. Do not repeat the missions that are already boring if you do not add other more curious, like for example "find XXXXX in some city of your neighbors / friends".
Giving the same use to the coins is not very flashy. I finish the 64 battles negotiating the 4th level and it is feasible to do it with a high expenditure of goods, obviously, and activating the extra turn.