I believe it came about during the "Windows must run on tablets" era. They needed a way for WiFi to stay on during sleep so things like notifications would continue to work. It also enabled media players to continue playing audio in sleep mode, similar to iOS and Android.
I tried a few times as some BIOS have a hidden or disabled setting but I never got past a plain crash. Device and CPU vendor support for classic S3 is shrinking. E.g. on framework laptops the Intel CPU(!) does not officially support S3 sleep.
So I can understand that there is no option for it if all you can get is out of spec behavior and crashes.
Also note that it is incompatible with some secure boot and system integrity settings.
> It also enabled media players to continue playing audio in sleep mode
Is that actually a thing? On my Windows machine media stops playing when I put it to sleep. The machine is clearly not completely off, though, judging by the fan spinning like crazy from time to time.
Also, the whole "keep checking for e-mails" and whatever is clearly broken, since after waking up Outlook needs a while to come back to life and show new messages.
Would be great to have a bios switch for it then.