When someone deletes the kanban view and later creates a new kanban view, all buckets are lost and all tasks remain in a “Backlog” bucket. Since it’s very easy to delete and restore views, I think it more convinient, when buckets are kept until they are explicitely deleted
Tested on Vikunja api version v0.23.0+509-ce1d7778c7
Buckets are deleted when deleting a view to clean up “orphan” buckets where the buckets still exist but their view doesn’t. Since a bucket is not only “this is the title of the bucket” but also “these tasks are in that bucket and on that position”, this can be quite a lot of data if there are many tasks. If a view is deleted, you don’t have any way of deleting the bucket to clean up that data. And there isn’t really a way to restore the view, so we’d need to introduce some kind of thrash bin where you could restore them as well, adding a lot more complexity.
I see! I thought of them as more of a container that only represents a 1:n relation from a bucketname to it’s tasks, but then let me emphasize on https://community.vikunja.io/t/manage-views-only-for-project-admins 
Well a bucket is a distinct object in Vikunja. They are more than just their name so it makes sense from the data model to see them as that.