Fishing docks primarily focus on the production of fish, which is used in various recipes and eaten as-is. Not all maps have ocean access so products produced here can be exported to those maps for a higher price.
The fishing dock can also be used as a house.
A dog will guard your stores from sneaky foxes.
Unlocks another workspace upgrade
A small fire in your house that keeps you warm during the cold months.
Allows you to build fishing boats (max 6) that will automatically be used by your workers. Fishing boats catch extra fish beyond the standard production and offload at the end of the day.
Comfortable Working Conditions
Invest in a nicer working environment for your workers. Adding more workers to a single production will become much more efficient.