I think the bigger use case is being able to (backoff) retry failing API calls to 3rd party services. AFAIUI the new tasks package doesnt offer this in v1 which is a deal breaker for my project, at least.
For me I think it works well as is because my use case is sending several different emails after POST'ing to a view, which, there is no need to make the user wait for in my case, as they don't care about the status of the mail delivery.
But I realize there are many other usecases too that will need proper workers.