OCaml (Reason) was my entry point into Typed FP (after a few failed attempts at learning Haskell). The best thing about OCaml is that it allows side-effects, so one can go a long way without having to touch advanced FP.
It is only recently that I've started getting comfortable with concepts cogently explained in this post, so to me it is quite valuable.
As an aside, I think OCaml/Reason/Elm should become the de-facto Typed FP entrypoint for programmers instead of Haskell. That'll help drive more adoption for the paradigm because the ecosystem is a lot more approachable and one wouldn't feel overwhelmed to even begin.
I would add F# to that list, which is an ML language as well.
It works on almost any platform, be it web, mobile, desktop or server via Fable, Xamarin or .NET Core.
It can work as an object-oriented language as well, which makes it easier to interface with C# code, but the documentation makes it very clear that functional is the way to go for F#.
For UIs there are libraries like Fabulous and Elmish, that provide a very similar programming model as Elm does.
You can even share code between all your target platforms:
I learned typed FP from Haskell, coming from JS, and I'm glad I started there.
It was a bit of a slog, but there are some wonderful books out there. I don't think we should discount the amount of pedagological resources that are available in the language. My favorite is the "First Principles" book.
As a side effect, I found that once I had learned most of Haskell (minus some of the language extensions aimed at type level programming). You pretty much won't find anything in any other typed language that will surprise you.
I understand your point of view and I also don't think my understanding of Typed FP would be complete without sufficient immersion in Haskell. But even with the learning materials, it is too steep a climb for beginner programmers for whom the love of the subject is secondary to their day jobs and regular life.
For people from dynamically typed or static OO background, being able to write functional code with records and sum types alone is a huge quality of life improvement. They should be able to get there with the least amount of effort. Haskell however demands far too much understanding and effort before it can be confidently used in a commercial setting. That excludes mainstream programmers who could otherwise most benefit from the paradigm.
I love Haskell, I find it a joy to write. If you don't really enjoy it then there isn't much reason to spend time on it. It's probably not going to help you with employment. As a side benefit, it's helped me solidify many PLT and CS concepts. That's enough for me to see value in it.
Similar for me. Tried to get into typed FP multiple times with no luck, but then I built a couple of web services with F# + Giraffe and an app in Bolero. It let me take my time getting into FP concepts and incorporate them along the way
It is only recently that I've started getting comfortable with concepts cogently explained in this post, so to me it is quite valuable.
As an aside, I think OCaml/Reason/Elm should become the de-facto Typed FP entrypoint for programmers instead of Haskell. That'll help drive more adoption for the paradigm because the ecosystem is a lot more approachable and one wouldn't feel overwhelmed to even begin.