We have an Active Sprint (Agile) Board with many columns (like To Do, In Progress, Done, etc.) that currently display subtasks in the appropriate column based on status, but the main tasks span across all rows with a little label that displays their status.
I understand that the purpose is to make it obvious that, regardless of status, all the subtasks belong to that task. That being said, it would be easier to visually determine the status of the tasks themselves if they were jammed into a column (just like subtasks), even if tasks-in-columns might need to be formatted differently to somehow differentiate them from subtasks and/or make it obvious that all subsequent subtasks were part of that task.