Sometimes the standard statuses don't quite fit a unique or one-off use case or need, but to add a new permanent stage would be clunky and potentially disruptive. Plus it would take up bloat and space. Instead, the ability to add "adhoc" statuses that apply only to that specific task or project would be a clear and straightforward way to handle unexpected emergencies or delays, etc. For reference, Motion has a similar feature: https://www.usemotion.com/blog/introducing-adhoc-stages