Yes! I’ve been building web applications for 15 years, but queuing systems were rarely discussed with any importance. I only picked up on it in the past few years, but since then, I consider it one of the most commercially-beneficial ways to scale and grow most kinds of software.
When it comes to scaling, it seems like 90% of the advice just focusses on RDMS, optimising indexes, etc. Database theory is vitally important to understand, but I now consider queue theory essential knowledge for modern application developers too.
Case in point: over the years I’ve reviewed thousands of PHP projects, articles, blogs, and other resources in the ecosystem. There are more guides to scaling Nginx or optimising MariaDB than I could ever need.
But I simply never see any discussion or usage of the low-level queue features offered by the language, like Deques: https://www.php.net/manual/en/class.ds-deque.php
I appreciate these have niche use cases, but a background queue handler builds on this kind of understanding, and is general purpose.
Knowledge of queue theory directly helped me scale my own projects, in ways I couldn’t have imagined otherwise.