I feel like there are scenarios where it's convenient to have a plain text string that is certain not to gum up parts of the system that would choke on punctuat

I feel like there are scenarios where it's convenient to have a plain text string that is certain not to gum up parts of the system that would choke on punctuation or a leading digit (see for example this package-mapping yaml: https://github.com/ros/rosdistro/blob/master/rosdep/base.yaml https://github.com/ros/rosdistro/blob/master/rosdep/base.yam...). Of course, Fedora 19 is codenamed `schrödinger` including the unicode character, so that's been an interesting experiment in ensuring that all the systems which ingest and process the codenames can handle that. Anyway, the obvious thing is that a codename is more fun and memorable than a number; it's something to hang marketing and such off of. Presumably this is why MacOS versions have always had public codenames since 2002. But I think the practical reasons are valid as well.