The age of great navigation 1404 what's the use of connecting castles, old trees, monasteries and witches of robbers and nobles?

There are robbers (strongmen) in the castle. After the connection, you can ask them to send troops by giving them certain materials, which is only useful in war. Old trees and witches are the same thing, and they can be divined, which is especially useful in the event of a large-scale plague. The monastery can sell you materials, which are very useful in the early stage and useless in the later stage.

In addition, there are archaeological remains, the Wisdom Academy and the Golden Pagoda, which can be used to excavate treasures, train captains and sailors and buy special props, all of which are of great use.