It means we can run higher compression in our engines without engine knock, which means we can run our turbos and timing harder on a smaller dispacement engine without ruining it, meaning more efficient engines.

Cleetus McFarland ran a car on brake-clean which has really low octane rating so sure anything works if you care about nothing. https://youtu.be/0hYOgGYQ_c8

American big block naturally aspirated engines will be tuned for crap fuel, if you've got a modern efficient turbo engine you should buy premium fuel to not ruin your engine.

I'd love to know which new big block naturally aspirated American cars don't recommend premium fuel. I think the low octane fuel is really only there for the older cars (and for folks who don't understand octane ratings).