When creating new tasks the task type field is not mandatory, therefore tasks can be created without a task type. There is no way to filter tasks for a blank task type, so there is no way to find these tasks easily.
My take on your question is that the Status Filters checkboxes work correctly with blank task types. The status New is assigned automatically upon creating a task and the other status checkboxes can also filter/find any blank task types that have been changed to other status designations.
Yes @kbens0n, other filters still pick up the tasks with a blank task type (when task type filter is all tasks). There is no way to filter specifically for blank task type.
I understand the point you raise now. You’d have to scroll the list instead of isolating blank types. ツ