thermal management is the first thing that comes to mind. and battery management

You would hope both those systems have built in hw failsafes

A blown fuse is a failsafe but that’s not helpful for users.

If they removed the hardware failsafes from speakers to save a cent per device, I wouldn't be so sure.

In the case of speakers, though, what would a hardware failsafe even look like? It would probably be some sort of secondary chip; Apple's design is to just move that to the main processor, the same way they don't have separate SSD controllers.

Monitoring the CPU temperature feels very different to me. I'm pretty sure the CPU can't cook itself. This is probably documented somewhere so we don't need to speculate, but I can't research right now...