Starting with release 2.3.0, queued scripts, on the other hand, do not and cannot affect the processing of the original API call. Both the request and response of the event are saved along with the script and queued for later execution. Queued scripts are primarily useful for triggering other workflows that need to be done when an event happens, but not necessarily during the processing of the event.
As mentioned in the article you referred, the
.queued event can be triggered in the same way as post and pre-process events.