Similar to the .220 Swift, the main purpose imo the .222 is the upper limit of meat and fur damage on rabbits, hares and foxes. Headshots preferred. Body shot on a closer rabbit leaves a body parts puddle. Longer shots better.

My first rifle was a steel bar Remington 788 in .222. Super accurate behind par. Used in countless rabbits, hares, foxes, hoppers, feral goats, some pigs, a fair few deer.

As for the .223 being "better'. I have a combination rifle barrel in .223. The .223 was invented as an ineffective military cartridge for guys that couldn't shoot. Maybe improved since with heavier bullets and faster twist. Of course better in a semi auto or full auto.

The .223 another wannabe. Otherwise no better than the original .222. And being slightly faster, the same or worse damage on fur and meat.

My opinions.