1) It is not a command that someone "uses", it's a script written by a programmer to be run for a business task or an end user quite likely may not "use Unix" (by your definition) ever.

2) The script goal most likely is not to make Unix work for you - it was originally written to make Unix do task X for you; but the goal/question in the OP is how to make that program more maintainable. Maintainability is an important goal, and to achieve that it's definitely acceptable to mutilate the way you usually do one-off tasks manualy.

3) The shell script is written for non-shell-script users - it's quite likely some glue for a system where 99.9% is in other languages, and the maintenance guys will specialize in those languages, and may not "use Unix" in their daily tasks at all. It's very common and reasonable to write all your code on a Win or Mac computer and then have it deployed to some linux server; and most companies currently do have separate ops teams (which would "use Unix" every day) and developer teams, which might "use Unix" once a month or less, even if the end binaries run on Unix.