As I understand it, swap is used even when the system isn’t under direct memory pressure. If the kernel sees that some memory is barely, if ever used, it will

As I understand it, swap is used even when the system isn’t under direct memory pressure. If the kernel sees that some memory is barely, if ever used, it will swap it out preemptively. This gives you more memory available for both programs and temporary caches. As such it’s still advantageous to add much more swap than this, since it effectively gives you extra free space in RAM at essentially no cost.