I once took over a certain repository that builds a dozen or so disparate external libraries with dependencies between themselves. The original developer of the repository did it by manually remembering which library had which dependencies and running .bat scripts to build them in order.

When I took over it, I wrote a PS script to automate the whole build. The script contains a description of each library's dependencies, so it knows what order to build all the libraries in. Each library is built in its own "job" using Start-Job, so the builds are also maximally parallelized; the script is essentially a loop of two functions: `for each library -> if library's dependencies have all been built -> start parallel job to build library` and `for each job -> if the job has finished -> mark the library as built`.

I would not write it in C#. Most of the build steps for each library involve running other processes, so using a shell DSL rather than multiple Process.Start()+Process.WaitForExit() is convenient. Even things like copying files is more convenient using Copy-Item than C#, especially since the PS versions support globs.

I would hope a build tool counts as both rigorous code as well as justifies PS as a programming language.

Aside: The repository was forked by some other people who did not like / could not read PS, so they rewrote it in Python. The Python version is several times larger than the PS version, though to be fair to it it's also more generic and has more features. A lot of that verbosity though does come from the more verbose code for spawning processes from Python compared to PS.