If you're actually using OSX's word list, each "digit" could be one of ~235886 words, which is more than 17 bits of entropy or the equivalent of 2-3 normal keyb

If you're actually using OSX's word list, each "digit" could be one of ~235886 words, which is more than 17 bits of entropy or the equivalent of 2-3 normal keyboard characters (and a lot of luggage lock tumblers). In practice few people are going to remember how to spell words like "aceanthrenequinone" correctly so the practical dictionary size is a lot smaller, but still in the tens of thousands of possible words. The xkcd comic says 44 bits for a 4-word combination of common words.