Docbase fields in documents contain references but are not checked when referenced item is deleted

The Document Type Editor provides a primitive field type "Docbase" that can be used in document types. It's basically a String field that lets you pick a content item from the repository, then stores that item's UUID in a String property.

Currently such a reference is not checked when deleting the referenced item (as is done in case of virtual node links).

This seems to me to be inconsistent. Also this difference between "Docbase" and "Link" compound type is not clear to the end user.