You act like the "I can persist data" is the part that matters. It's the fact that I can from my pool of app servers post a unit of work to be done and be sure it will happen even if the app server gets struck down. It's the architecture of offloading work from your frontend whenever possible to work that can be done at your leisure.

Use whatever you like to actually implement the queue, Postgres wouldn't be my first or second choice but it's fine, I've used it for small one-off projects.