It's simple, small, clean, and Turing Complete. Most others show "interesting behaviour" (for some definition thereof) but are not Turing Complete (though some

It's simple, small, clean, and Turing Complete. Most others show "interesting behaviour" (for some definition thereof) but are not Turing Complete (though some are). I've not found a CA that's Turing Complete and as small and easy to understand (which is not to say there isn't one).