In the Alt Actions Docs for action.defer it is written
This is a method that faciliates calling multiple actions in another action. Since multiple actions cannot be fired until the dispatch loop has finished this helper function waits for the dispatch loop to finish and then fires off the action. It is not recommended but it is available anyway.
What I'm wondering about is Why is it not recommended to use action.defer? and what is the best practice for calling multiple actions asynchronously, one after the other?