This doesn't actually tell you how far you can go without a message queue. Unsurprising because they're trying to sell one. But you can go very far without them by using the DB or redis as your message queue. Probably fine for 99%+ of applications.
Don't add a message queue until you really need one. And if you do make sure you account for it being down, running locally, back pressure if the queue gets full, monitoring, and logging at least.
You probably dont need a message queue if you have redis. And quite a lot of code surrounding it. Which also makes it a message queue. Example: [0]
What you might mean is that you might not need a complicated server setup e.g. Kafka for simple message queues?