It's a small amount of effort for a thousand-fold increase in performance and not having to re-implement the same functionality in every app and in every language that connects to that DB. YMMV.
The argument was between using SQL in stored procedures or SQL in queries sent by the application, so you don't have to re-implement anything (just share the SQL queries between apps), and I very much doubt you'll get a thousand-fold increase in performance.
It's a small amount of effort for a thousand-fold increase in performance and not having to re-implement the same functionality in every app and in every language that connects to that DB. YMMV.