Basically what happened is that I created that feature 1-2 weeks before the bunq update where bunq released the official savings goals. So now bunqDesktop has both :p
The savings goals page are separate from the bunq savings goals and are only something for bunqDesktop. The custom one has more options and lets you set a goal spread over multiple accounts for example. You can easily combine the custom and official one by creating a new custom savings goal and set the goal amount to the bunq savings account goal.
I thought about merging the two but since the custom system allows for a lot more functionality I decided to keep both. One thing I could do is automatically create a custom savings goal when a new savings monetary account is opened but I'm open to suggestions.
The export/import buttons are there to export and import the custom savings goals just like is possible with the category rules and other features within bunqDesktop.