I don't understand how the queue system works?

Question

Redis

1) When registering a user, a message is sent to the user about successful registration. But the data has not yet been added to the database and is waiting in line. Then it turns out that we can rarely use queues due to constant delays if we need instant information. For example, when sending a comment, we want to see it immediately in the list of comments, and not wait until its turn comes.
2) Or is it a balancer that sends data to the database immediately after adding a comment, just distributes the load using queues?