What do you mean by discoverability? What is the bar? Like is `:=` not discoverable in python. Or are ternaries not discoverable in Javascript? I'd say these are equally mysterious to a new learner. Just because $ is unfamiliar, doesn't mean it's worse than any other language construct.

Also, literally the first hit when you google “what does $ do in Haskell” is an explanation. So it’s in the docs, easily googlable, and one of the first things all learning material explains. How is that not discoverable?

No, it really doesn't. It values language ergonomics higher than learnability. That doesn't mean learnability is valued at 0. It has nothing to do with discoverability.