His ending bit where he talks about hitting a ceiling that you can't really break out of sums up my experience writing Elm. It's a good teaching language too and does good at that.
Elm really is a gem. It's like an "approachable browser Haskell". And the Elm Architecture makes it really easy and fun to handle your state and the view(s) into it.
Every time I want to sit down and write an elm app I have a great time until I need to do anything complex.