I should have formulated the question in a better way; my students probably won't take another shot at FP for a looong time after this course, so I don't want them to lose too much on the more "fun" parts of FP, because they might just never see them if I don't show them.
So I was wondering what limitations would Elm impose, apart from the typeclasses, compared to Purescript (Haskell).
Nested record updates are also not supported, so u have to write functions to update each record field.
Elm is by design a very opinionated language, which is good for beginners usually since there is only one chosen way to do things but not so for experienced devs.
The fun parts of FP are still present in elm, it's completely pure side effect free, great type checker with awesome error messages, fast performance and great for building interactive web apps with it's TEA architecture.
It's really awesome for debugging complex ui interactions but not for actual line by line code debugging