I use this to store IP addresses in a database because you can operate on numbers (e.g. WHERE subnet_start < $thisip < subnet_end) but hardly on the unique dotted format that we normally display them as.

Also to specify a bind address when I don't care, like running `php -S 0:3000` (the silly thing wants a bind address rather than only a port number. There, have one!) or accessing localhost in a browser (just typing 0:3000 is enough). For 127.0.0.1, unfortunately the best you can do is writing 127.1. The numeric, hex, and octal variants are 2130706433, 0x7f000001, and 017700000001, which I personally don't find preferable to 127.1.