What is Tavern and what does it do?

Tavern is a large building in your home area where you can cook several different delicious dishes. Here characters will request a dish order and you need to send the order to fill the bar and receive rewards. As you send more orders, you will fill the bar and get chests that bear keys. Once you receive those keys, you can use them to open the chests that are washed ashore to get even more rewards.