Why Restore Old Buildings?

Why should old buildings be restored? Is there a cultural value to it? Would it help the people living in Transylvania, and improve the combined value that Transylvania (and its many names that Transylvania is called) has to the world. Here are two pictures below

Elizabeth Bathory's Castle: IS there value in restoring this castle or are the native plants around there more vital? ( They are in some cases endangered.)

One of the ancient castles of Alba Iluia: Would it be better if restored? What if it was the castle that Michael the brave entered in?