It just comes down to a habit of giving a name to something as an example of something that isn't meant to map to any problem domain. E.g. when a manufacturer is in the business of making "widgets," we know they're not actually making products that are widgets (whatever those are.)

Once you know that the names being used are not considered to be "important", the other names aren't as important as well, only the syntax. These metasyntactic variables are useful for avoiding situations like "Who's on First?" (e.g. https://www.youtube.com/watch?v=kTcRRaXV-fg ) which is humorous to native-English speakers, but probably incoherent to non-native English speakers.