I should have been more explicit. The main advantage is people can communicate using (and short-term memorize) the trigesimal geocode much easier than the Lat/Lon DD Coordinates. The trigesimal geocode in theory could even be used as a Postal Code. Of course we can also store 8 characters instead of 10 to save space in the database; simply drop the last character from x_cd and y_cd.
From the NAC (Natural Area Code) website (http://www.nacgeo.com/?page_id=11)
"... an eight-character NAC is an ideal universal address for postal services, delivery services, emergency services and taxi services because it can specify an area less than 25 by 50 meters anywhere in the world."
"... a ten-character NAC is a perfect property identity code for each property in the world, which specify a reference area less than 0.8 by 1.6 meters on a property anywhere in the world."
What is true for the NAC is true for any trigesimal geocode system. This is good news because the NAC is heavily IP encumbered (which it shouldn't be IMHO). It uses '0123456789BCDFGHJKLMNPQRSTVWXZ' as a character set and I have '0123456789BCDFGHJKLMNPQRSTVWXY' in the SQL script; simply swap 'Y' for 'Z' to convert back. You can use any character set you like, for example, '0123456789abcdefghijklmnopqrst' would be valid as well. Using a set without vowels not only avoids 1/I, 0/O confusion, it means your geocode will never be a word, profane or otherwise.