Channels, currently implemented with a Redis backend, provide an at best one-off guarantee, while Celery provides an at least one-off guarantee. This essentially means that Celery will retry when a delivery fails until it receives a successful acknowledgment. In the case of Channels, it is pretty much fire-and-forget. Secondly, Channels does not provide information on the status of a task out of the box. We need to build such functionality ourselves, for instance by updating the database. Celery tasks status can be queried and persisted.
