SQL is the most high level language in common use. It abstracts away everything: Storage, memory, concurrency, and, most importantly, control flow. Complexity comes from complecting things, simplicity comes from decomplecting [1] things. SQL decomplects the what (data flow) from the how (control flow) which means less cognitive load, higher developer productivity and better maintainability.
In my experience, writing business logic in SQL results in fewer bugs and less code. I have replaced 50-line Java methods with 15-line SQL projections multiple times. With Python, the ratio is closer to 2:1, but it's still impressive.
And all of this without having to consider type impedance, eager versus lazy loading, result set mappings, second-level caching, dirty tracking, lifecycle management, OCC, or obscure savepoint bugs. Performance is just a nice, but welcome side effect.