Perhaps we were all just not good at database'ing, but at a previous job, "using RDBMS as a queue" became a meme/shorthand for "terrible idea that needs to be stamped out immediately".
Does Postgres have some features that make it not entirely unsuitable to use for queuing?
I think this is one of the cases where "You don't have Google problems, so you don't need Google solutions" applies. Using Postgres or a RDBMS for queuing is perfectly fine and it'll get you a long way before you have to worry about scaling or optimizing it.
The benefits are easy to see: You already know how to operate a database, you can easily see what's the in the queue, you can easily insert items in the queue with a simple "insert" query, you can use triggers to enqueue items that got changed etc.
In the end, a queue is relatively simple to switch out later.
Does Postgres have some features that make it not entirely unsuitable to use for queuing?