0. https://www.cloudamqp.com/blog/why-is-a-database-not-the-rig...
EDIT>> I am not suggesting people build their own rabbitmq infrastructure. Use a cloud service. The article is informational only.
A message queue is one of those things that is easy enough and worth the effort to do "right" early on, because it is not something you want to rip out and rewrite when you hit your scaling bottlenecks, given how critical it is and how many things it will end up touching.