In our project board we like to keep current epics visible as their own column/cards with an estimated number of story points. Work in these epics tbc is broken down into appropriately sized tasks/features/cards which have to be spec’d as:
Subtasks (then not clearly visible for WIP columns)
Standalone card (which can’t be meaningfully back-linked to epic cards)
Feel as though epic cards could be a useful feature, allowing back-linking of separate, visible cards. And also to automatically total story points of linked work to ensure it matches with epic, track epic velocity etc.