You are absolutely right, but not every project needs reliable messaging. Many projects can be just fine with ephemeral messaging, they might already have some

You are absolutely right, but not every project needs reliable messaging. Many projects can be just fine with ephemeral messaging, they might already have some kind of managed scalable database and failures can often be handled on the client side. Often we insert messaging into an HTTP system, or replace an HTTP system. In those cases, the client is waiting for an acknowledgement from the system that sits on the other side of the queue. What happens in HTTP is you send a request to an HTTP server, but it combusts before you get a responce? Connection breaks or you get "request timed out" and user can click the button again. Or you can retry in the client code. For many joke apps it is not always worthwhile to double complexity to move from a 98% system to a 100% system.