It’s not a piece of software worked on by a team though. It’s a personal project, written to by one person to be understood by that person, and incidentally I think some effort has been made to make the code easier to read for random passers-by on the internet. Not every piece of code has to be written to meet the same goals, there is a large spectrum.

I write both terse notes to myself, and longer more well-thought out sets of notes to distribute to undergraduates in classes I teach. I wouldn’t give the undergraduates my personal notes - they are simply too unpolished and terse - but my colleagues find them very helpful on occasion. Is it wrong to have two different ways of writing?

I would say this C implementation leans somewhere between “note to self” and “arty exploration”. Is it worth being written? I don’t think you or I could be the judge of that, but the author obviously thought so. Live and let live.