Using an LLM to generate code is not an easily traceable and explainable process. Using a DSL to same ends is. PL research has yet to meet explainability in AI head on.
As an avid designer of CS courses and curricula in the not-so-distant past, I would like for it turn into a success criterion that your course gets included in this listing.
Back when I was involved in designing the BSc education at the University of Copenhagen, I remember referring the committee to the ACM/IEEE-CS/AAAI Computer Science Curricula. Great to see that there has been an update to these recently, complete with a Generative AI section and all :-)
>> does any important software use APL nowadays?
> No.
That's not a question one is able to answer objectively in this world full of closed source software.
Large parts of SimCorp (https://en.wikipedia.org/wiki/SimCorp) Dimension, a suite of software for investment management used by a fair number of European banks and pensions funds, are written in APL. That said, Dyalog exists, and SimCorp does not play any grand role in its existence. So there must be others out there. The mere existence of APL keyboards is proof that there is a market for these things.